Remove unnecessary db indexes

[MarceloRobert]

Some indexes in the production database were created automatically by kcidb, but we don't need some of them considering that we don't use some fields in where conditions and the excess of indexes can degrade performance. Some of the kcidb indexes are also duplicates of django automatic indexes.

• Issues:
  • issues_report_url
• Checkouts:
  • checkouts_git_commit_hash_patchset_hash (we should still have an index on commit_hash alone with Create more indexes on dashboard db #1351, but we don't need an index on patchset_hash)
  • checkouts_git_repository_branch_tip
  • checkouts_origin_builds_finish_time
  • checkouts_origin_tests_finish_time
  • checkouts_start_time_idx (duplicate of checkouts_start_time)
  • checkouts_valid
• Builds:
  • builds_checkout_id (duplicate of builds_checkout_id_e340e47e)
  • builds_checkout_id_idx (duplicate of builds_checkout_id_e340e47e)
• Tests:
  • tests_build_id (duplicate of tests_build_id_551a24f9)
  • tests_number_unit
  • tests_number_value
  • tests_origin_start_time_idx
• Incidents:
  • incidents_build_id (duplicate of incidents_build_id_dfa49727)
  • incidents_issue_id (duplicate of incidents_issue_id_5ef3a289)
  • incidents_present
  • incidents_test_id (duplicate of incidents_test_id_5d40ff84)

[nuclearcat]

Indexes dropped:

DROP INDEX CONCURRENTLY IF EXISTS public.issues_report_url;

DROP INDEX CONCURRENTLY IF EXISTS public.checkouts_git_commit_hash_patchset_hash;
DROP INDEX CONCURRENTLY IF EXISTS public.checkouts_git_repository_branch_tip;
DROP INDEX CONCURRENTLY IF EXISTS public.checkouts_origin_builds_finish_time;
DROP INDEX CONCURRENTLY IF EXISTS public.checkouts_origin_tests_finish_time;
DROP INDEX CONCURRENTLY IF EXISTS public.checkouts_start_time_idx; -- duplicate of ...start_time
DROP INDEX CONCURRENTLY IF EXISTS public.checkouts_valid;

DROP INDEX CONCURRENTLY IF EXISTS public.builds_checkout_id;
DROP INDEX CONCURRENTLY IF EXISTS public.builds_checkout_id_idx;

DROP INDEX CONCURRENTLY IF EXISTS public.tests_build_id; -- duplicate of ..._551a24f9
DROP INDEX CONCURRENTLY IF EXISTS public.tests_number_unit;
DROP INDEX CONCURRENTLY IF EXISTS public.tests_number_value;
DROP INDEX CONCURRENTLY IF EXISTS public.tests_origin_start_time_idx;

DROP INDEX CONCURRENTLY IF EXISTS public.incidents_build_id; -- duplicate of ..._dfa49727
DROP INDEX CONCURRENTLY IF EXISTS public.incidents_issue_id; -- duplicate of ..._5ef3a289
DROP INDEX CONCURRENTLY IF EXISTS public.incidents_present;
DROP INDEX CONCURRENTLY IF EXISTS public.incidents_test_id; -- duplicate of ..._5d40ff84

[MarceloRobert]

Checked. There will just be some renaming needed for 3 indexes:
checkouts_git_commit_tags turned into checkouts_commit_tags
checkouts_git_repository_branch turned into checkouts_git_branch
checkouts_git_repository_url turned into checkouts_git_url
And it's possible to use ALTER INDEX IF EXISTST name RENAME TO new_name.

So we still need:

ALTER INDEX IF EXISTS checkouts_git_commit_tags RENAME TO checkouts_commit_tags;
ALTER INDEX IF EXISTS checkouts_git_repository_branch RENAME TO checkouts_git_branch;
ALTER INDEX IF EXISTS checkouts_git_repository_url RENAME TO checkouts_git_url;

[MarceloRobert]

Checked. Done.