[Feature Request] Enhanced search/filter feature for discovered files

Issue Type: Feature Request
Issue Description:

Related issue(s): #953

**Problem**

The new UI brings noticeable performance improvements when browsing individual file discoveries when compared to the old one.

However, it lacks the ability to apply search filters across all files in the project as tree view, something the old UI would let you do.


This makes it difficult for users to efficiently identify and resolve cases like "NOASSERTION" or "OTHER" due to the fact that the individual files (sometimes many) need to be filtered down and examined.

But as made apparent in issue #953, the new UI appears only to apply the search filter within the folder depth you are currently in.

Take the [following case](https://clearlydefined.io/definitions/git/github/rescrv/hyperdex/148334d53e76cc03808854050ebcb5addffe3c7c), for example:

We are in the root of the project's source tree and can see there are two license discoveries we can filter down.


First, we select BSD-3-Clause option which shows us there are some files under this license already present in the root directory.


Next, we want to look at the NOASSERTION findings, but unfortunately nothing is shown when that option is selected.


However, we're still determined to turn over that NOASSERTION stone, so we take a detour and search the raw data.

This extra effort reveals that the _./m4_ directory as well as a few others have a NOASSERTION discovery.


And... if we apply the same NOASSERTION filter within that directory, we see it filters down to just that one result.


So from how it appears, the column filter in the current Files tab only shows items in the user's current "working" directory.

**Solution Proposed**

Implement a "global file search" either as an independent and separate search field, or as "enhanced" version of the current column-based filter that can be configured by the user to show files outside their current working directory depth.