VSCE: Create search and search UI packages

Created by: tjkandala

The VS Code extension depends on a lot of search code. For example, components such as <StreamingSearchResultsList> or types like QueryUpdate .

In the VS Code MVP draft PR, I refactored and moved dependencies shared between web and vscode to the branded (for styled UI) or shared (for utilities, types) folders. However, that doesn't align with our vision of having focused, standalone workspaces.