Set implementation version in config by default

[CasperWA]

Set config defaults for provider and implementation.
This ensures that the version field is set for implementation.

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Maybe all of this is not needed?
But it's important to get the version sub-field automated here.

[codecov]

Codecov Report

Merging #385 into master will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #385      +/-   ##
==========================================
+ Coverage   90.22%   90.24%   +0.01%     
==========================================
  Files          55       55              
  Lines        2404     2408       +4     
==========================================
+ Hits         2169     2173       +4     
  Misses        235      235              

Flag	Coverage Δ
#unittests	90.24% <100.00%> (+0.01%)	⬆️

Impacted Files	Coverage Δ
optimade/server/config.py	100.00% <100.00%> (ø)

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[shyamd]

I chose to do this via the default values in the config so that someone using a modified version of our server could update the implementation.

Your code also overrides the provider no matter who is using it.

[CasperWA]

I chose to do this via the default values in the config so that someone using a modified version of our server could update the implementation.

Your code also overrides the provider no matter who is using it.

It doesn't override. It sets the defaults first, then updates the values with the provided ones - the same for the implementation.
However, I also see issues with this, specifically that all these values are OPTIONAL.
But also version is OPTIONAL - and I quite like the small feature that it dynamically retrieves __version__ from the package ...
But I can just minimize it so that only version is preset and then updated afterwards with the supplied provider config parameters?

[shyamd]

Just to clarify, we have no way of knowing how to fill in the Provider fields when someone provides partial information. It's very possible they want the other fields to be empty.

[ml-evs]

LGTM!