Add 1 favorite locally when you favorite an app

[RKBoss6]

When you favorite an app, the text inside the icon adds one favorite immediately, that is local and will not get pushed to the database. What this PR does is gives the illusion that the website is updating the favorites immediately, adding another layer of feedback that the user has favorited an app. This has been tested, and works with no problems.

Example: When I favorited an app before, the color fill of the heart icon would change, but not the number, since the database is not updating with every favorite. eg. (30 --> 30)

Now, if I favorite the app, the text goes from 30 --> 31, which instantly provides feedback that you indeed favorited the app, and the number has changed.
Hopefully this will help the website feel more snappy and efficient with favorite handling.

• Add local favorites variable to keep track of favorites made in session
• Add local saving so the added favorite doesn't disappear on refresh
• Remove local favorite when database is updated

[RKBoss6]

The editor I'm using seems to have formatted the document differently than before, leading to a bit of a nightmare for maintainers... Hopefully I can get that fixed 🤞

[gfwilliams]

Thanks! This looks good (apart from the maybe global variable favsThisSession?), but I really don't want all the random whitespace changes that are in there now!

If you could fix that I'd be happy to pull it in. I guess it might be easier for you to stop the editor messing it up, then just start from scratch and copy in the few lines of changes you made?

[RKBoss6]

Thanks! I think that's what I'll end up doing anyway - it's a bit of a mess right now.

[RKBoss6]

It's fixed now, and works well!

[gfwilliams]

Looks great - thanks! Just merging