Search: retain the existing view settings when displaying results

Currently, if the view is a grid and a search is performed, we switch to list view. There are good reasons for this - list view emphasises the file names, and allows relevant information to be shown about the results.

However, there is a couple of arguments against switching to list view:

• If the view is a grid view, it is because the user chose that view, and it is the view that is best-suited to their needs. Maybe they want to see the thumbnails, for example.
• It is disruptive - the transition to list view requires a user to do cognitive work.

Show the directory for grid view results?

Search results from subfolders are the main challenge with using grid view for search results. For these results, we need to show the path in order to differentiate between otherwise identical results.

One possible approach would be to show the name of the result's directory, as a caption:

However, this approach is not without its issues:

1. It will require adjusting the grid layout, which could be disorientating
2. Showing the directory and not the path will fail in some cases (meson.build files in src or data directories being an obvious example)

Thoughts?

@jimmac @snwh @bertob