Add verbose support

[vdeshpande7]

What does this change do? Please be clear and concise.

Add verbose support to PyCustodian to support logging.DEBUG.

Why was this change made? Including an issue number is sufficient. Otherwise, briefly explain the benefit of the change.

Add verbose support to PyCustodian as an optional arg. If the argument is set to TRUE, set Level to logging.DEBUG.

Verification

List the steps needed to make sure this thing works. Be precise.

1. From the command-line, run ...
2. The output should look like this: ...
3. If you pass some bad value, the output should look like this: ...
4. ...

• Verify the thing does this: ...
• Verify the thing does not do that: ...

Affirmations

All of these should have a check by them. Any exception requires an explanation.

• I have added docstrings with details on keyword arguments to new functions following the convention detailed in this gist
• I have added type hinting to new function parameters.
• I have added tests to new functions, following the rules of F.I.R.S.T..
• I matched the style of the existing code.
• I added and updated any relevant documentation (inline, README, CHANGELOG, and such).
• I used Python's type hinting.
• I ran the automated tests and ensured they ALL passed.
• I ran the linter and ensured my changes have not introduced ANY warnings or errors.
• I have made an effort to minimize code changes and have not included any cruft (preference files, *.pyc files, old comments, print-debugging, unused variables).
• I have made an effort maintain a clear commit history (haven't merged other branches or rebased improperly).
• I have written the code myself or have given credit where credit is due.