codeintel: Install and use the LSIF upload route on the codeintel internal API

Created by: efritz

The precise-code-intel-indexer-vm goes through the public API, but this requires that a sudo sourcegraph access token be given to the indexer. Instead, we can use the same token-based auth we have for the other routes hit by this service and install the same handler to a second route.

Created by: codecov[bot]

Codecov Report

Merging #13157 into main will increase coverage by 0.00%. The diff coverage is 52.63%.

@@           Coverage Diff           @@
##             main   #13157   +/-   ##
=======================================
  Coverage   49.53%   49.53%           
=======================================
  Files        1472     1472           
  Lines       82113    82128   +15     
  Branches     6724     6724           
=======================================
+ Hits        40677    40685    +8     
- Misses      37832    37838    +6     
- Partials     3604     3605    +1     

Flag	Coverage Δ
#go	52.52% <52.63%> (+<0.01%)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
enterprise/cmd/frontend/internal/codeintel/init.go	0.00% <0.00%> (ø)
...ntend/internal/codeintel/internal_proxy_handler.go	45.94% <0.00%> (-0.63%)
...-code-intel-indexer-vm/internal/indexer/handler.go	65.15% <71.42%> (+1.00%)
internal/db/helpers.go	100.00% <0.00%> (ø)
internal/gosrc/stdlib.go	100.00% <0.00%> (ø)
internal/conf/platform.go	100.00% <0.00%> (ø)
internal/routevar/util.go	100.00% <0.00%> (ø)
internal/timeutil/week.go	100.00% <0.00%> (ø)
internal/vcs/git/mocks.go	100.00% <0.00%> (ø)
internal/db/query/query.go	100.00% <0.00%> (ø)
... and 732 more