refactor(detector): standardize db.NewDB to db.CloseDB

[MaineK00n]

What did you implement:

db.Close(), which was the cause of this issue(#1281), was handled differently in OVAL, gost, exploitdb, metasploitdb, and kevuln.
This time, we will refactor it so that all of them use the same method to get the client and close the DB.
Also, the method to determine whether it is a DB or HTTP is based on whether the driver, which is the minimum data, is nil or not. In addition, I decided to have only the URL to the dictionary (baseURL) so that it does not need to be as large as the config.

Fixes #1121
Duplicate PR #1272

In addition to refactoring the client around, I incorporated the following issue and PR content.
When there is no config.toml (configPath is ""), read environment variables and enable reporting.

Type of change

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

$ OVALDB_SQLITE3_PATH="/usr/share/vuls-data/oval.sqlite3" GOSTDB_SQLITE3_PATH="/usr/share/vuls-data/gost.sqlite3" CVEDB_SQLITE3_PATH="/usr/share/vuls-data/cve.sqlite3" EXPLOITDB_SQLITE3_PATH="/usr/share/vuls-data/go-exploitdb.sqlite3" METASPLOITDB_SQLITE3_PATH="/usr/share/vuls-data/go-msfdb.sqlite3" KEVULN_SQLITE3_PATH="/usr/share/vuls-data/go-kev.sqlite3" go run cmd/vuls/main.go report -config "" -refresh-cve
[Feb  7 01:28:43]  INFO [localhost] vuls-`make build` or `make install` will show the version-
[Feb  7 01:28:43]  INFO [localhost] Validating config...
[Feb  7 01:28:43]  INFO [localhost] cveDict.type=sqlite3, cveDict.url=, cveDict.SQLite3Path=/usr/share/vuls-data/cve.sqlite3
[Feb  7 01:28:43]  INFO [localhost] ovalDict.type=sqlite3, ovalDict.url=, ovalDict.SQLite3Path=/usr/share/vuls-data/oval.sqlite3
[Feb  7 01:28:43]  INFO [localhost] gost.type=sqlite3, gost.url=, gost.SQLite3Path=/usr/share/vuls-data/gost.sqlite3
[Feb  7 01:28:43]  INFO [localhost] exploit.type=sqlite3, exploit.url=, exploit.SQLite3Path=/usr/share/vuls-data/go-exploitdb.sqlite3
[Feb  7 01:28:43]  INFO [localhost] metasploit.type=sqlite3, metasploit.url=, metasploit.SQLite3Path=/usr/share/vuls-data/go-msfdb.sqlite3
[Feb  7 01:28:43]  INFO [localhost] kevuln.type=sqlite3, kevuln.url=, kevuln.SQLite3Path=/usr/share/vuls-data/go-kev.sqlite3
[Feb  7 01:28:43]  INFO [localhost] Loaded: /home/mainek00n/github/github.com/MaineK00n/vuls/results/2022-02-07T01:10:16+09:00
[Feb  7 01:28:43]  INFO [localhost] OVAL debian 11.2 found. defs: 23046
[Feb  7 01:28:43]  INFO [localhost] OVAL debian 11.2 is fresh. lastModified: 2022-02-07T01:08:55+09:00
[Feb  7 01:28:44]  INFO [localhost] vuls-target: 0 CVEs are detected with OVAL
[Feb  7 01:28:45]  INFO [localhost] vuls-target: 203 CVEs are detected with gost
[Feb  7 01:28:45]  INFO [localhost] vuls-target: 0 CVEs are detected with CPE
[Feb  7 01:28:45]  INFO [localhost] vuls-target: 3 PoC are detected
[Feb  7 01:28:45]  INFO [localhost] vuls-target: 0 exploits are detected
[Feb  7 01:28:45]  INFO [localhost] vuls-target: total 203 CVEs detected
[Feb  7 01:28:45]  INFO [localhost] vuls-target: 0 CVEs filtered by --confidence-over=80
vuls-target (debian11.2)
========================
Total: 203 (Critical:15 High:64 Medium:89 Low:16 ?:19)
0/203 Fixed, 34 poc, 0 exploits, cisa: 0, uscert: 0, jpcert: 3 alerts
319 installed

$ OVALDB_SQLITE3_PATH="/usr/share/vuls-data/oval.sqlite3" GOSTDB_SQLITE3_PATH="/usr/share/vuls-data/gost.sqlite3" CVEDB_SQLITE3_PATH="/usr/share/vuls-data/cve.sqlite3" EXPLOITDB_SQLITE3_PATH="/usr/share/vuls-data/go-exploitdb.sqlite3" METASPLOITDB_SQLITE3_PATH="/usr/share/vuls-data/go-msfdb.sqlite3" KEVULN_SQLITE3_PATH="/usr/share/vuls-data/go-kev.sqlite3" go run cmd/vuls/main.go server -config ""
[Feb  7 01:23:26]  INFO [localhost] vuls-`make build` or `make install` will show the version-
[Feb  7 01:23:26]  INFO [localhost] Validating config...
[Feb  7 01:23:26]  INFO [localhost] cveDict.type=sqlite3, cveDict.url=, cveDict.SQLite3Path=/usr/share/vuls-data/cve.sqlite3
[Feb  7 01:23:26]  INFO [localhost] ovalDict.type=sqlite3, ovalDict.url=, ovalDict.SQLite3Path=/usr/share/vuls-data/oval.sqlite3
[Feb  7 01:23:26]  INFO [localhost] gost.type=sqlite3, gost.url=, gost.SQLite3Path=/usr/share/vuls-data/gost.sqlite3
[Feb  7 01:23:26]  INFO [localhost] exploit.type=sqlite3, exploit.url=, exploit.SQLite3Path=/usr/share/vuls-data/go-exploitdb.sqlite3
[Feb  7 01:23:26]  INFO [localhost] metasploit.type=sqlite3, metasploit.url=, metasploit.SQLite3Path=/usr/share/vuls-data/go-msfdb.sqlite3
[Feb  7 01:23:26]  INFO [localhost] kevuln.type=sqlite3, kevuln.url=, kevuln.SQLite3Path=/usr/share/vuls-data/go-kev.sqlite3
[Feb  7 01:23:26]  INFO [localhost] Listening on localhost:5515
[Feb  7 01:23:48]  INFO [localhost] OVAL debian 11.2 found. defs: 23046
[Feb  7 01:23:48]  INFO [localhost] OVAL debian 11.2 is fresh. lastModified: 2022-02-07T01:08:55+09:00
[Feb  7 01:23:49]  INFO [localhost] vuls-target: 0 CVEs are detected with OVAL
[Feb  7 01:23:50]  INFO [localhost] vuls-target: 203 CVEs are detected with gost
[Feb  7 01:23:50]  INFO [localhost] Fill CVE detailed with gost
[Feb  7 01:23:50]  INFO [localhost] Fill CVE detailed with CVE-DB
[Feb  7 01:23:50]  INFO [localhost] vuls-target: 3 PoC detected
[Feb  7 01:23:50]  INFO [localhost] vuls-target: 0 exploits are detected

Checklist:

You don't have to satisfy all of the following.

• Write tests
• Write documentation
• Check that there aren't other open pull requests for the same issue/feature
• Format your source code by make fmt
• Pass the test by make test
• Provide verification config / commands
• Enable "Allow edits from maintainers" for this PR
• Update the messages below

Is this ready for review?: YES

Reference

[kotakanbe]

There is one point that could be a nil pointer, so please fix it.

[kotakanbe]

Confirmed that make diff was successful.