Create a GraphQL wrapper API for extensions

[tjkandala]

Closes #15069.

[codecov]

Codecov Report

Merging #15566 (c96bc1b) into main (565f3ae) will decrease coverage by 0.00%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##             main   #15566      +/-   ##
==========================================
- Coverage   52.36%   52.36%   -0.01%     
==========================================
  Files        1604     1604              
  Lines       80224    80227       +3     
  Branches     7141     7071      -70     
==========================================
  Hits        42013    42013              
- Misses      34530    34534       +4     
+ Partials     3681     3680       -1     

Flag	Coverage Δ
go	52.48% <ø> (+<0.01%)	⬆️
integration	28.61% <0.00%> (-0.03%)	⬇️
storybook	26.24% <0.00%> (-0.01%)	⬇️
typescript	52.08% <66.66%> (-0.02%)	⬇️
unit	34.47% <66.66%> (+<0.01%)	⬆️

Impacted Files	Coverage Δ
client/shared/src/api/client/connection.ts	84.61% <ø> (ø)
client/shared/src/api/extension/extensionHost.ts	76.47% <ø> (ø)
...lient/shared/src/api/extension/flatExtensionApi.ts	97.70% <50.00%> (-1.13%)	⬇️
client/shared/src/api/client/mainthread-api.ts	100.00% <100.00%> (ø)
...ient/web/src/search/input/LazyMonacoQueryInput.tsx	77.77% <0.00%> (-22.23%)	⬇️
...lient/web/src/search/results/SearchResultsList.tsx	73.12% <0.00%> (-1.25%)	⬇️
.../internal/codeintel/resolvers/graphql/locations.go	81.44% <0.00%> (+2.06%)	⬆️

[felixfbecker]

Nice!

[felixfbecker]

Got a couple more thoughts but otherwise looks fine!