feat(seer grouping): Add Seer fields to grouphash metadata table

[lobsterkatie]

This adds fields to the GroupHashMetadata table to track the following for hashes sent to Seer:

• When the grouphash was sent to Seer
• Which event's stacktrace was sent (stored as an event id)
• The Seer model version used to analyze the stacktrace
• The matched hash returned by Seer, if any (stored as a reference to that hash's GroupHash record)
• The similarity distance returned by Seer, if any

Use of these fields is added in #78107.

[wedamija]

migration lgtm. The table has only 14k rows so adding the index is fine.

[github-actions]

This PR has a migration; here is the generated SQL for src/sentry/migrations/0769_add_seer_fields_to_grouphash_metadata.py ()

--
-- Add field seer_date_sent to grouphashmetadata
--
ALTER TABLE "sentry_grouphashmetadata" ADD COLUMN "seer_date_sent" timestamp with time zone NULL;
--
-- Add field seer_event_sent to grouphashmetadata
--
ALTER TABLE "sentry_grouphashmetadata" ADD COLUMN "seer_event_sent" varchar(32) NULL;
--
-- Add field seer_match_distance to grouphashmetadata
--
ALTER TABLE "sentry_grouphashmetadata" ADD COLUMN "seer_match_distance" double precision NULL;
--
-- Add field seer_matched_grouphash to grouphashmetadata
--
ALTER TABLE "sentry_grouphashmetadata" ADD COLUMN "seer_matched_grouphash_id" bigint NULL;
--
-- Add field seer_model to grouphashmetadata
--
ALTER TABLE "sentry_grouphashmetadata" ADD COLUMN "seer_model" varchar NULL;
ALTER TABLE "sentry_grouphashmetadata" ADD CONSTRAINT "sentry_grouphashmeta_seer_matched_groupha_c92b0107_fk_sentry_gr" FOREIGN KEY ("seer_matched_grouphash_id") REFERENCES "sentry_grouphash" ("id") DEFERRABLE INITIALLY DEFERRED NOT VALID;
ALTER TABLE "sentry_grouphashmetadata" VALIDATE CONSTRAINT "sentry_grouphashmeta_seer_matched_groupha_c92b0107_fk_sentry_gr";
CREATE INDEX CONCURRENTLY "sentry_grouphashmetadata_seer_matched_grouphash_id_c92b0107" ON "sentry_grouphashmetadata" ("seer_matched_grouphash_id");