support "port" in oracle connection

[qsliu2017]

Currently, when oracle DSN is provided with a port, e.g. oracle://localhost:1234/db, the cx_Oracle driver will report

'port' is an invalid keyword argument for this function

Accordding to the docs, cx_Oracle support port in dsn parameter:

If the database is using a non-default port, it must be specified:

connection = cx_Oracle.connect(user="hr", password=userpwd,
                               dsn="dbhost.example.com:1984/orclpdb1",
                               encoding="UTF-8")

This PR parses port from data-diff into host of cx_Oracle, thus supports port number in oracle connection.

close #370

[qsliu2017]

Hi there, will my PR be reviewed?

[skaosYan]

Hey! can someone review this PR?

[dlawin]

makes sense

[dlawin]

Appreciate the contribution @qsliu2017 !