Remove reference to "all" endpoint and rename collections submodule

[ml-evs]

Just a couple of tiny changes that I'm happy to leave out:

• Removed the "all" endpoint from the default endpoint list in BaseInfo. I couldn't find a reference to this in the spec, so assume it was an old macro? Currently writing a validator that scans "available_endpoints" of a reference implementation and makes requests against them and don't want to have to hardcode ignoring all.
• Renamed the server.collections submodule as it clashes with the standard library collections, it's not a big deal, but opening vim from that folder was causing it to crash...

[codecov]

Codecov Report

Merging #73 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master      #73   +/-   ##
=======================================
  Coverage   85.71%   85.71%           
=======================================
  Files          30       30           
  Lines        1323     1323           
=======================================
  Hits         1134     1134           
  Misses        189      189

Impacted Files	Coverage Δ
optimade/models/baseinfo.py	92.3% <ø> (ø)	⬆️
optimade/server/entry_collections.py	82.5% <ø> (ø)
optimade/server/main.py	66.18% <100%> (ø)	⬆️

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[CasperWA]

* Removed the `"all"` endpoint from the default endpoint list in `BaseInfo`. I couldn't find a reference to this in the spec, so assume it was an old macro? (...)

Correct. This endpoint was officially removed from the spec. in v0.10.0.

* Renamed the `server.collections` submodule as it clashes with the standard library `collections`, it's not a big deal, but opening vim from that folder was causing it to crash...

Great! I did this in my local server as well - so very much needed.

[CasperWA]

All good for me 👍

Thanks @ml-evs!