UI: Avoid file browser directory change if path didn't change

E.g. entering the file path field and then pressing enter without any
change would call an unneccesary directory change, causing flickering.
So the main point of this is to avoid flickering.

Without this the text field could also be used to refresh the file list,
but for that we have a proper button.

UI: Replace big options button in file browser

The big options button in the lower left is now gone, it's replaced by a
smaller icon toggle button in the upper right.
That means I could also remove code for the region we had just for this
button.
I also added versioning code for the removal, to make sure the region is
removed cleanly when reading old files.

UI: Use vertical file list for "Recover Auto Save"

Pablo and William agreed that the main purpose of the layout should be
to list files in a way that it's easy see which files were
created/modified when. Previously it was set to "Long List" to show the
modification time, now the vertical list is much better suited. The time
is shown anyway.

Remove redundant file bookmarks region toggle operator

For the default keymap we were only using the regular toolshelf
operator, doing this for the industry compatible keymap too now (we
could even remove it there, we don't use it in other editors).

Since we "now" have proper operators for toggling regions, this specific
one is totally redundant.

Refactor: Ensure there's always a valid file editor tool region

So far the file browser code had some lazy creation for the tool region,
even though it should always be there. The only reason I can see for
this is compatiblity. So I simply added versioning code to add the
region in case it's not there. Now we should be able to savely assume
the tool region to be there, whithout any unusual lazy-creation.

Rewrite file region handling for non-editor mode

This makes it so that regions only needed when the file browser is
invoked as an operation (e.g. Ctrl+O rather than a regular editor) are
lazy created then, and removed if the file browser is changed into a
regular editor then (e.g. Ctrl+O over regular file browser editor ->
Cancel).

That should remove some troublesome assumptions and makes versioning
redundant.
It also fixes the issue of an empty execute region at the bottom after
cancelling a file operation invoked from a regular file browser editor.

Cleanup: Add/use utility to remove regions

Fix empty file options region in regular editor

This would happen when opening a file browser as regular editor, opening
a temporary file browser from there (e.g. Ctrl+O) and cancelling the
operation.
In some cases this would cause most of the editor to be filled with an
empty operator options region:
* Go to Shading workspace
* File -> Append
* Cancel

Fix Preferences opens file browser in wrong window

Steps to reproduce were:
* Open Preferences in a new window (Edit -> Preferences)
* Set file browsers to open fullscreen (Interface->Editors->Temporary
Windows)
* Open a file browser in the Preferences (e.g. Add-ons -> Install)
The file browser would be opened in the parent window, rather than the
preferences.

Fix T70048: Assert when cancelling Append window

If the file browser was opened from an existing file browser editor
(using File -> Append would make the mouse hover the file browser in the
Shading workspace), we need special handling for closing the fullscreen
area.
This change brings back the old way of handling fullscreen closing.