Added a "lerp" and "once" prop to Favicon

[NathanKoehler]

Added a lerp and once option to favicon, lerp will cause the animation to play in reverse on completion and once, when animated is false and once is true, will cause the animation to play once. Once and lerp also work together in that when once and lerp are both true, the favicon will play the reverse animation to return to the original state. Otherwise it will simply return to the initial position.

[oflisback]

Hi @NathanKoehler thanks for taking the time to do this, it looks useful.

Please use prettier to format the code in the PR and if you are up to it it would be nice if you also demonstrated usage in the example app (see the app under example/).

I'm about to update the tool-chain for this repo but this PR probably go in first. :)

[oflisback]

Hi @NathanKoehler, the big changes I mentioned have been merged, I'm sorry that it made the merge of this PR harder. If you'd like to give it another go please go ahead. If you do, then consider to install the prettier extension in vs code (or similar if you use another editor) for a cleaner patch. If you like I can make the additions to the example app.