Support URL shortening for shared web links

[kendallroth]

The shared day message is quite lengthy with the addition of an HTTP redirect link (required for most message platforms, see #15). This could be improved by implementing a URL shortening system of temporarily storing shared URLs in a simple JSON storage mechanism, and providing a shortened URL that would be cleaned up after usage. Coupled with the website for redirects, this could provide a decent experience with a far shorter link.

This could potentially also replace direct mobile links???

A day has been shared with you from My Days! Follow this link to add 'Friend's Wedding' to the app!

exp://192.168.2.11:19000/--/day/shared?date=2023-04-13&icon=ring&id=2f306ada-0b6b-4b9c-ab4b-2d12a66c6f0b&repeats=false&title=Friend%2527s%2520Wedding&version=1

Alternative (web redirect)
https://my-days.kendallroth.ca/mobile/redirect?url=exp%3A%2F%2F192.168.2.11%3A19000%2F--%2Fday%2Fshared%3Fdate%3D2023-04-13%26icon%3Dring%26id%3D2f306ada-0b6b-4b9c-ab4b-2d12a66c6f0b%26repeats%3Dfalse%26title%3DFriend%252527s%252520Wedding%26version%3D1