Application buttons - Allow adding & hiding buttons locally

Template authors might add multiple IDEs and editors to cater to a broader group. However, as an individual developer, I might only be interested in VS Code, not JetBrains IDEs. Thus, one can show and hide icons based on personal, locally stored preferences. These can be preferences stored in "global" settings, like the HTTP headers, or on a per workspace level.

The issue names no files, tests, or entry points. Start by locating application button rendering and the existing global or workspace preference storage, then determine how template-provided buttons are represented. Done means users can locally add or hide buttons, with preferences supported globally or per workspace.

Written by the indexing model from the issue text.