PGBouncer Configuration Screen

[noctarius]

We need a configuration screen for configurable values of PGBouncer.

The current model looks like:

{
  "pgbouncer_enabled": true,
  "pool_mode": "string",
  "max_client_conn": 0,
  "default_pool_size": 0,
  "server_idle_timeout": 0,
  "server_lifetime": 0,
  "query_wait_timeout": 0,
  "reserve_pool_size": 0
}

Updatable values are:

{
  "default_pool_size": 20,
  "max_client_conn": 100,
  "server_idle_timeout": 60,
  "server_lifetime": 600,
  "query_wait_timeout": 30,
  "reserve_pool_size": 0
}

The required API calls to get or update the values:

GET [/organizations/{organization_id}/projects/{project_id}/branches/{branch_id}/pgbouncer-config](https://dev.kernel-labs.org/vela/docs#/organization/organizations:projects:branch:get-pgbouncer-config)
PATCH [/organizations/{organization_id}/projects/{project_id}/branches/{branch_id}/pgbouncer-config](https://dev.kernel-labs.org/vela/docs#/organization/organizations:projects:branch:update-pgbouncer-config)