Change ScanPoliciesManager interface (see TODOs)

[mlech-reef]

ScanPoliciesManager.should_exclude_file should accept File object, not string
ScanPoliciesManager.should_exclude_directory should accept AbstractFolder object, not string

[mpnowacki-reef]

@mlech-reef Why is this needed for V2?

[mlech-reef]

It breaks compatibility.

[mpnowacki-reef]

@ppolewicz In light of

change all path arguments everywhere (internally too) to use pathlib instead of strings

from #139

should should_exclude_file and should_exclude_directory indeed use File and Folder and not pathlib.Path ?

[ppolewicz]

I think the problem here is that should_exclude_file and should_exclude_directory can have b2:// File / Folder passed into them and pathlib.Path doesn't support b2:// resources

[mpnowacki-reef]

The way ScanPoliciesManager.should_exclude_file and ScanPoliciesManager.should_exclude_directory work right now is they compare B2 paths to sets of regexes - even though it's not documented, they never operate on local paths. Even when invoked in LocalFolder, a would-be-B2-path of a dir or a file is constructed and passed to the appropriate ``ScanPoliciesManager.should_exclude_*` method. I'm not sure it would be beneficial to create "possibly-existsing-b2-file" objects when scanning local folders just to match their paths against regexes.

@mlech-reef Is this interface change somehow needed elsewhere? Or do you need access to all B2File versions (carried by B2File) in your implementation of ScanPoliciesManager ?

[mpnowacki-reef]

However, changing the interface to have the following methods:

• should_exclude_local_file accepting a LocalFile object
• should_exclude_b2_file accepting a B2File object
• should_exclude_local_folder accepting a LocalFolder object
• should_exclude_b2_floder accepting a B2Folder object

and performing the translations internally would make for a clean, extensible API. The problem is that ScanPoliciesManager objects would need access to local_dir and b2_dir to perform translations accurately. Or maybe a subdelegate of ScanPoliciesManager, a policy manager aware of the particular sync context?

[mlech-reef]

@mpnowacki-reef The TODO was created just to not operate on str-like object carrying paths. Just for that.