use tsdb config for initializing index gateway client

[sandeepsukhani]

What this PR does / why we need it:
We were temporarily using boltdb-shipper config for initializing the index gateway client. This PR fixes it by doing relevant updates.

[grafanabot]

./tools/diff_coverage.sh ../loki-main/test_results.txt test_results.txt ingester,distributor,querier,querier/queryrange,iter,storage,chunkenc,logql,loki

Change in test coverage per package. Green indicates 0 or positive change, red indicates that test coverage for a package fell.

+           ingester	0%
+        distributor	0%
+            querier	0%
+ querier/queryrange	0%
+               iter	0%
+            storage	0%
+           chunkenc	0%
+              logql	0%
-               loki	-0.1%

[DylanGuedes]

lgtm!

just a note: maybe in the future we can tweak the TSDBShipperConfig and the BoltDBShipperConfig to somehow be shared, to avoid the duplications (like the ones in modules.go)

[sandeepsukhani]

lgtm!

just a note: maybe in the future we can tweak the TSDBShipperConfig and the BoltDBShipperConfig to somehow be shared, to avoid the duplications (like the ones in modules.go)

yeah, that is the plan. We are temporarily going with duplicate configs. I would love to move it to a shipper config which would be shared by boltdb-shipper and tsdb but that can't be done cleanly without breaking backwards compatibility.

[kavirajk]

LGTM!. One minor nit.

[grafanabot]

./tools/diff_coverage.sh ../loki-main/test_results.txt test_results.txt ingester,distributor,querier,querier/queryrange,iter,storage,chunkenc,logql,loki

Change in test coverage per package. Green indicates 0 or positive change, red indicates that test coverage for a package fell.

+           ingester	0%
+        distributor	0%
+            querier	0%
+ querier/queryrange	0%
+               iter	0%
+            storage	0%
+           chunkenc	0%
+              logql	0%
-               loki	-0.1%