Add filter input to group members table

[robertknight]

Add a search box to filter group members. The filter currently only matches the username, is applied client-side and is case-insensitive.

Filter not applied:

Filter applied with match:

Filter applied with no matches:

[robertknight]

In the client we have a SearchField component that has additional features compared to a plain input such as a search icon, support for focusing by pressing "/" and a "clear" button when non-empty. It might be useful to extract that into the shared library so we can use it here.

[acelaya]

In the client we have a SearchField component that has additional features compared to a plain input such as a search icon, support for focusing by pressing "/" and a "clear" button when non-empty. It might be useful to extract that into the shared library so we can use it here.

I believe we have something similar in via's video transcript app, so it definitely makes sense to extract a component that can be reused.

[robertknight]

The filtering and member count are currently implemented client side, but once we have pagination they will need to be implemented server-side. This means we will probably need to temporarily remove this until more critical functionality is implemented.