Add Acquire collection loader

[Matthijsy]

This PR adds a loader for ZIP files, which is mainly useful for ZIP based acquire collects.

I don't have experience with creating loaders, and mainly took the logic from the TarLoader. So if there are things that can be done better would be happy to improve!

fixes #934

[Horofic]

First of all, thanks for you contribution @Matthijsy. I think this is a good first attempt :)!

As you kind of pointed out, the ZIPloader mainly took the logic from the TarLoader with some minor tweaks. I think a better way forward would be to create an AcquireLoader that works on both Zip, Tar and Dir based Acquire collections! Kind of like the VelociraptorLoader found here. Here it does some specific checks to see if a collection is
is a Velociraptor collection.

Let me know what you think about this!

[Horofic]

Could you add tests for this new functionality? This could be done later, if you decide to go on the AcquireLoader route.

[Matthijsy]

@Horofic Thank you for the feedback, that indeed sounds like a good plan. I have now changed it to a dedicated AcquireLoader. This way it seems to work for both the zip and directory types. However, the directory mapping for the tar version does not work yet. When I test this using target-shell the root directories look like this

c:
fs0
fs1

I suspect that the find_and_map_dirs does not handle the tar format correctly, but I cannot figure out how to add support for that. Could you give me some pointers in how to do that?

Furthermore, I suspect this will not work anymore for the legacy acquire format as described in the TarLoader logic. Is this still something that should be supported?

[Horofic]

Posting this comment for documentation purposes. @Matthijsy and I had a discussion outside of this PR regarding possible approaches for this AcquireLoader.

@Matthijsy one possible approach we haven’t gone over is described and implemented in PR #700 by @Zawadidone. I believe some changes have to be made to the current TarFilesystem implementation to be able to go this route.