Added queries to limit the scan scope via the --scope input param

[blupants]

This PR addresses issues:

• Jira scan, add possibility to use JQL to limit the scope of the scan [issue 33]
• DeprecationWarning: Flags not at the start of the expression [issue 30]

You can now define queries (such as JQL for Jira, CQL for Confluence, GitHub search, Slack search or Zendesk search)

Python 3.6 introduced the DeprecationWarning: Flags not at the start of the expression warning. The point is that the Python re now does not allow using inline modifiers not at the start of string. In Python 2.x, you can use your pattern without any problem and warnings as (?s) is silently applied to the whole regular expression under the hood. Since it is not always an expected behavior, the Python developers decided to produce a warning. In order to fix that, this PR modifies the regex ingestion behavior, so every-time a modifier is found not in the beginning of the regex, n0s1 will move it to the beginning.

Sample queries to limit the scan scope

Scan all projects in Jira except MAR:

n0s1 jira_scan --email marcelo@spark1.us --server https://spark1us.atlassian.net --scope "jql:project != MAR"

Scan only projects MAR and "Auto Service" in Jira:

n0s1 jira_scan --email marcelo@spark1.us --server https://spark1us.atlassian.net --scope "jql:project=MAR OR project=\"Auto Service\""

Scan all pages from workspace KB in Confluence:

n0s1 confluence_scan --email marcelo@spark1.us --server https://spark1us.atlassian.net --scope "cql:space=KB and type=page"

Scan only Slack messages with the word "database":

n0s1 slack_scan --scope "search:database"

Scan only GitHub repos from the org spark1security with the word "action" in the name:

n0s1 github_scan --debug --scope "search:org:spark1security action in:name"

Scan only Zendesk tickets with the word "AWS" in the title:

n0s1 zendesk_scan --email securebycode@gmail.com --server cybersecurity9851 --scope "query:type:ticket subject:AWS"