Show & Hide Schemas

### Is your proposal related to a problem?

The schemas created by other Postgres plugins like (timescale) are showing up in the dashboard. We need a way to hide & show them. Otherwise, it's getting too much clutter

### Describe the solution you'd like

For each database, we have a source dashboard. In that dashboard, we need to have a button near the schema for hiding the schemas.

### Describe alternatives you've considered

We can add a button near each schema to hide them in the side bar but for a frequent user, its might be annoying.

### If the feature is approved, would you be willing to submit a PR?

Yes

Start in the per-database source dashboard and its schema list, focusing on the proposed control near the schemas and the sidebar behavior shown in the issue images. Define how a user hides and restores schemas for each database, then verify that the dashboard no longer shows hidden schemas and that they can be shown again.

Written by the indexing model from the issue text.