Add support for suffix after mount point for autofs

[3x14]

This adds the ability to modify the suffix after the mount point.

This introduces two new options in the configuration: suffix and prefix
prefix: A regular expression to capture a prefix, or mount point.
suffix: A regular expression to modify the prefix.

If you have :ufs-33-a.i
This allows you to easily change the suffix: ufs-33-a.ib

The config file for this operation would look something like this:
[suffix]
suffix_base = ""
suffix = ""

I used ConfigParser inside files.py, but I am guessing that will need to be changed.

[jaqx0r]

Thanks for the contribution!