Add search bar in Custom Views feature

[ce-bo]

Feature request

Description

As a user, I want custom configs to be easily understandable and easy to use so that I do not have to invest a lot of time using them.

Tasks

• [ ] Add a search bar that allows to search for custom configs by name, metric, mode, groupname (if implemented already) or similar parts. Use e.g., "🔎 Custom views..." as default text that is hidden on focus. Provide a "X" button to clear the input of the search field. (It should be a simple search field that filters the Custom Views in the list on keystroke).
• [ ] Show a message when no Custom Views could be found for the user's search.