fix: can manually (or opt-in to automatically) check for updates

[fmaclen]

• Can opt-in to check for updates automatically
• If enabled, it checks for updates once a week
• Can manually check for updates regardless of auto-update setting
• It shows update instructions based on the Hollama server environment

[fmaclen]

:tada: This PR is included in version 0.10.3 :tada:

The release is available on GitHub release

Your semantic-release bot :package::rocket:

[fmaclen]

@GregoMac1 just wanted to let you know of some changes this PR introduced that you'll likely interact with:

• $settingsStore now has default values when it's created, so we no longer need to check if it's undefined
• There is a new route /api/metadata endpoint that returns the app's version and the environment
• In /settings, I split the different sections into separate components because having all of that logic together was hard to read.
• I added the new i18n keys to the root of the tree.
  • Related: I also created #171 (which we should do before #151)