Verify GEO installation with PostgreSQL 11

After PostgreSQL 11 is bundled in omnibus-gitlab, we need to ensure that fresh installations of GEO are functional with PostgreSQL 11.

We should verify the following scenarios

1. Single node primary, and single node secondary instances
2. Separate database nodes on both primary and secondary
3. On the secondary, running with separate postgresql, and geo-postgresql nodes

Blocked by #4969 (closed)

1. Single node

Tests:

• Repository
• Mirrored repository
• Wiki
• Uploads (wiki)
• LFS objects
• Job artifacts

2. Separate database nodes

Tests:

• Repository
• Mirrored repository
• Wiki
• Uploads (wiki)
• LFS objects
• Job artifacts

3. All databases separated

Tests:

• Repository
• Mirrored repository
• Wiki
• Uploads (wiki)
• LFS objects
• Job artifacts