feat(gui): Limit search to a package

[andyjsmith]

Adds the ability to limit search to a specific package (and sub-packages).

Often, you want to search for some code inside a specific package. The only way to do this currently is to add exclusions for all the packages you don't want, perform your search, and then include the packages again.

This PR adds:

• The ability to specify a package in the search window to limit the search to
• A "Text search" option to the right-click menu of all packages in the tree. This opens the search with the package name pre-filled in the field.

This works for all search providers (except for resources, which just ignores the restriction if enabled).

Build passes with gradlew clean build dist

This is my first contribution here so please feel free to let me know your questions/thoughts/concerns!

Resolves #1408 and part of #818

[skylot]

@andyjsmith great work 👍

There is one minor possible improvement: split events processing for package search/verify with triggering search. So if package change we first search matching package object and if found than trigger big search. This way package field will be interactive and will notify about incorrect package even if "auto search" is disabled. Not sure if this really needed, so I might apply these changes myself later 🙂