[Feature] Add configuration option for excluding specific collectors as well as using a custom predefined set of collectors

[Lat3magnet1c]

To make the handling of collectors easier i added two configuration options for choosing collectors.
This configuration is implement analogue to the already existing secretsdump options in the donpapi.conf.
Both features can be considered as nice to have.

• The first option collectors_list specifies a list of collectors, which then can be used with -c Custom (analogue to -c All). This makes it easier when using a large set of collectors, as you can use the shortcut Custom to select your preferred collectors.
• The second option always_exclude specifies a list of collectors, which will always be excluded from the loaded collectors even when they are specifically named with the -c flag. If nothing should be excluded leave the field empty. This would also fix Feature request : enhance collector selection #115.

Furthermore i added a debug output for all loaded collectors before starting.

Hope this helps!

[Lat3magnet1c]

also added fix for #123