Fix for issue #381 / Unparsed config args

[vossen-adobe]

#381

Invocation Defaults for user-sync-config now parsed if they are list type correctly. Added small parser for ID to do this. It parses the key values such that they match the corresponding command line values.

For example, specifying groups in the invocation defaults now yields an input list of:
['group', 'GroupA,GroupB']

Previously, it was parsed as a single value like this:
['group "GroupA,GroupB"]

Which could not be intepreted as a valid argument.

This fix resolves other list inputs as well:
eg, adobe-only-user-action write-file xyz.csv now works too from invocation defaults.

[adorton-adobe]

@janssenda-adobe - It's not clearly documented, but I believe the intent is for compound arguments such as --users group "GroupA,GroupB" or --users file users.csv to be specified as arrays.

users: ['group', 'GroupA,GroupB']
users: ['file', 'users.csv']

If a string is passed to list-type invocation default (like connector or users), it will be added to a single-element list in DictConfig.get_list().

        if value is not None and not isinstance(value, list):
            value = [value]

Thank you for looking into this, but I'm going to close this PR since it's a documentation issue and not a bug with the config module. I've already created an issue to update the documentation - #387

Would you mind reviewing the doc update when I finish it?

[vossen-adobe]

@adorton-adobe absolutely!