Re-add the "sort by date and website" in the new History sidebar

[BelFox]

This option is currently not foreseen in the revamped History sidebar (see Firefox Nightly).

[Example]

Let's say you browse github.com on a daily basis.

• In Firefox 130 (release), I can go to "Yesterday" and go to the folder "github.com" to search for pages that I know I visited on Github yesterday. Quick and easy!
• In the new History sidebar, I can see all the history for "github.com", but I won't know which pages I visited yesterday. Alternatively, I can see all the history for "yesterday", but I won't have the github pages grouped, making it more difficult to find them between the other (chronologically sorted) history. Using the search is not always the solution, because sometimes you don't remember the title of the page you're looking for. Having them combined in a folder per website makes it easier to find them back.

[Proposed changes]

• When "sort by date" is active, visited pages are sorted by their timestamp (new to old). In this way, it replaces both the old "Sort by recently visited" and "Sort by date" options. Implemented ✅
• When "sort by date and website" is active, visited pages are sorted alphabetically (just like when "sort by website" is active). Visited pages are first grouped by date (using collapsible headers), next by website (using collapsible folders). See mock-up in attachment.  ⏳Waiting for implementation