Add support for running GitLab Geo tracking database

Secondary Geo Nodes will need a separate PostgreSQL tracking database to store progress. This MR depends on https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/1197.

database_geo.yml.example

+development:
+  adapter: postgresql
+  encoding: unicode
+  database: gitlabhq_geo_development
+  pool: 5
+  host: /home/git/postgresql-geo
+
+test: &test
+  adapter: postgresql
+  encoding: unicode
+  database: gitlabhq_geo_test
+  pool: 5
+  host: /home/git/postgresql-geo