Fix broken usage of previous keylist files

[cavejay]

Last year I broke a feature that told strippy to use a previously generated keylist file

2dd1b8b#diff-23980a80770b63f261e165fc6b2a1797R609

This was silly and needs to be revisited/fixed.

[cavejay]

This can be completely resolved by a more standard output keylist file.

Should be packaged up with Strippy v3.0 as a breaking change.

Possible keylist file format:

<Top of Keylist File from Config>

[Keys]
<spaced as a table with .ini style>
Hostname02      = example.com
Address1        = 127.0.0.1

[FileList]
<list of sanitised files - nl separated>