Voyager: Header bar improvements

[JL102]

Having the full Scoutradioz logo permanently in the header is arguably a waste of valuable screen real estate. Most apps show the title of the current page in the static header bar.
Instead of showing a h1/h2 element at the top of the page with the title, we should show the title where the Scoutradioz header logo currently stands. If there's enough space, we can show the radio icon next between the hamburger menu and the title. We can show the full Scoutradioz header icon inside the slide-in menu.

I would also like to show a subtitle with relevant info, like the team number someone is scouting, or the checksum of the match schedule, or the event name, something like that. This idea wasn't as popular during our brainstorm session, though.

Lastly: Need to fix the header not sliding away when you scroll down the page.