VFS Capability detection, other extensions about os.js HOT 6 OPEN

I continue with capability detection of VFS:
os-js/osjs-client#186
os-js/osjs-server#65

These changes are considered added method has some argument. If you still have the idea of capability caching, maybe we should create another PR that changes the api to support methods without arguments.
I remember I worked on this issue but did not come up with solution.

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As discussed, @mahsashadi will do some work related to this in the following stages:

1. URL serialization (done)
2. Client option filtering
3. Capability detection (done)
4. Other improvements

Massive thanks!

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Also, @ajmeese7 wanted to have a look at archive extensions.

Thanks a bunch!

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@mahsashadi Yeah, let's tackle the caching in a separate PR. It needs further discussion. I have some ideas about this already, but let's take it when the time is right.

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I continue with adding total values to VFS stat api (needed for pagination in file manager):
os-js/osjs-server#66

I also make another pull request for capability-caching:
os-js/osjs-client#188

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I made another PR for VFS context-aware sorting in client-side.
os-js/osjs-client#189

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