feat(store) replace Vuex settingsStore with equivalent Pinia store

[Antreesy]

☑️ Resolves

• Part of Vue 3 Migration #9448
• This PR as a beginner should be a proper example of how to migrate other stores - feel free to suggest changes!

🖼️ Screenshots

• No visual changes
• Only NewMessage Typing indicator and Talk settings private statuses switches are affected

🚧 Tasks

• Manual testing
• Code review

🏁 Checklist

• ⛑️ Tests (unit and/or integration) are included or not required
• 📘 API documentation in docs/ has been updated or is not required
• 📗 User documentation in https://github.com/nextcloud/documentation/tree/master/user_manual/talk has been updated or is not required
• 🔖 Capability is added or not needed

[ShGKme]

It seems that we also need to init Pinia at least in files sidebar app. And then we will need to init pinia in other apps used store.

All the other things looks great to me.

---

While I believe, moving to Pinia has only benefits and no drawbacks, I'm not sure we should do it now (as was discussed with @nickvergessen on the Talk Team week).

This is not a part of Vue 3 migration as both Pinia and Vuex are not linked to a specific Vue version. We can do it before the migration as well as after the migration.

Nevertheless, I'm personally fine to move to Pinia any time.

[Antreesy]

Rebased onto master because of conflicting package-lock.json

Also reverted prevously discussed changes regarding storing the capabilities

[ShGKme]

🍍 Tested, works fine 🍍

Note, OptionsApi-like define store was used here. It is easier for migration purpose and looks more structured. But CompositionApi-like defineStore have more possibilities, such as:

• More complex init
• Internal (aka private) methods and variables
• Possibility to use watch and etc.