Ability to share day configs

[kendallroth]

Request

Need to add the ability to "share" a day configuration with another user. This will not track changes, but will only create a duplicate item via the app (from a URL).

Features

• Ability to share a link (versioned?) for day configs
• Ability to open custom schema URLs (my-days://) and parse config
• Create a day from an external URL (maybe via confirmation dialog?)

Notes

• Users should be prompted to update app when attempting to open a shared day with a higher schema version
• App should attempt to parse non-matching shared day versions where possible (throw errors if invalid)

[kendallroth]

This may be a little more complex than originally thought, as React Native does not support sharing links on Android (docs). Instead, a potential (Stack Overflow solution) would be to send a known https:// link (from URL redirect service maybe???) that would then redirect to the desired custom scheme link 🤷.

[kendallroth]

Closed in #12