Draft: Feature: decomposition:connection_status: Include connection status

What does this MR do and why?

solves #450729:

Click to expand

> ### Problem to solve > >`gitlab-rake gitlab:db:decomposition:connection_status` shows the used and max connections of the Postgres database as long as the `ci:` section hasn't been created: > ``` ❯ gitlab-rake gitlab:db:decomposition:connection_status Currently using 42 connections out of 1337 max_connections, which is enough for running GitLab using two database connections. ``` > >This is pretty useful information to have. That behavior changes once the `ci:` section has been created to display a static message: https://gitlab.com/gitlab-org/gitlab/-/blob/v16.6.1-ee/lib/tasks/gitlab/db/decomposition/connection_status.rake?ref_type=tags#L8-11 > ``` ❯ gitlab-rake gitlab:db:decomposition:connection_status GitLab database already running on two connections ``` > >### Proposal > >Provide the connection info, even post `ci:` migration: > ``` ❯ gitlab-rake gitlab:db:decomposition:connection_status GitLab database already running on two connections

Currently using 42 connections out of 1337 max_connections, which is enough for running GitLab using two database connections.

>
>### Intended users
>
>[Sidney (Systems Administrator)](https://handbook.gitlab.com/handbook/product/personas/#sidney-systems-administrator) wants to check whether their Postgres `max_connections` is sufficient to accommodate the increased connection demand of GitLab [ter the deprecation of "single database connection".](https://docs.gitlab.com/ee/update/deprecations.html#single-database-connection-is-deprecated)

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## How to set up and validate locally

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Related to #450729