feat: Add support for custom global (Issue #1276)

[tcleonard]

Solution for issue https://github.com/graphql-python/graphene/issues/1276

[tcleonard]

This is an updated version of https://github.com/graphql-python/graphene/pull/1278 You can find on the old one the discussions around the feature

[erikwrede]

@ulgens Do you have time for a review?

[codecov[bot]]

Codecov Report

Merging #1428 (d1f6412) into master (b20bbdc) will increase coverage by 0.16%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1428      +/-   ##
==========================================
+ Coverage   95.72%   95.88%   +0.16%     
==========================================
  Files          50       51       +1     
  Lines        1683     1726      +43     
==========================================
+ Hits         1611     1655      +44     
+ Misses         72       71       -1     

Impacted Files	Coverage Δ
graphene/__init__.py	100.00% <ø> (ø)
graphene/relay/__init__.py	100.00% <100.00%> (ø)
graphene/relay/id_type.py	100.00% <100.00%> (ø)
graphene/relay/node.py	100.00% <100.00%> (+1.38%)	:arrow_up:

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[tcleonard]

@ulgens I have rebased on master and added a few tests to get full coverage. Do you mind double checking and approving so I can merge?