Add client-side manual time addition

[sh0ckR6]

The client needs a way to add time manually, it's a little hard to do this server-side

[sh0ckR6]

Assigning you on this @gtaEPIC if you don't mind because I can't do HTML/CSS :D

[gtaEPIC]

Looks like this will take a bit longer than I expected. A few other issues occurred while I was testing, so I'll fix those tomorrow

[sh0ckR6]

That's never what you want to hear 😅

If anything's out-of-scope on this PR, PR the fixes in their own one just to keep things organized