Implement essentials of the launcher

[alexrp]

• [ ] Main window with
  • [x] background image,
  • [x] logo,
  • [x] music,
  • [ ] and news articles.
• [x] Gateway and world server URI input (for non-vendored builds only).
• [x] Implement account flows:
  • [x] authentication,
  • [x] email change,
  • [x] password change,
  • [x] password recovery,
  • [x] and deletion.
• [ ] Account status display: (also show a popup when logging in)
  • [x] unverified,
  • [x] incomplete email change,
  • [x] deletion countdown,
  • [ ] ban reason/countdown.
• [ ] Installation, update, and repair flows for TERA.
• [ ] Update and repair flows for TERA Arise.
• [ ] Game launch flow.

[alexrp]

Scaffolded the Avalonia project. Most of this work can be started now.

[foglio1024]

Minor UI TODOs:

• [x] Find a main color (pink-purple from the Arise skill icon); current one is kinda dark
• [ ] Find an accent color
• [x] Find a background/base color for dark theme (bluish-gray from the current background)
• [x] Fix pointerover color of the main Login button
• [x] Implement login form visibility logic (registration, password recovery, etc will probably be the same form with different modes)
• [x] Maybe add an opacity gradient to the background to fade into the title bar
• [x] Apply main color to checkboxes
• [x] Figure out what to do with the account button in the title bar
• [x] Add some artistic decoration to the login form
• [x] Figure out how to make custom fonts work with current application structure
• [x] Add a button to toggle music

[foglio1024]

Added initial implementation if in-window modal visibility logic, but it appears to have bad performance on first display.

https://github.com/tera-arise/arise/blob/d65b61f4242d8857497b98801eac18784506921f/src/client/Launcher/Windows/MainWindow.axaml#L19-L30

Either figure out a way to render the form beforehand to have it ready when it's requested to become visible or maybe use an actual separate window for the form.

This might be related: https://github.com/AvaloniaUI/Avalonia/issues/1529

[foglio1024]

Next tasks:

• [x] Give some feedback to the user when re-sending verification email
• [x] Fix account creation failed text not fitting inside the button (maybe just show a popup instead)
• [x] Implement email change flow
  • [x] Add new email to verification response https://github.com/tera-arise/arise/blob/work/launcher-essentials/src/client/Launcher/Controllers/Modals/EmailChangeModalController.cs#L98
• [x] Implement password change flow
• [x] Implement account deletion flow
• [ ] Enhance modal container resize behavior by using this approach
• [x] Enable confirmation on enter key in forms
• [x] Focus the first textbox when opening/switching modals
  • [ ] (also when failing login, etc)
• [x] Save last used email if login was successful
• [x] ✨✨✨
• [ ] Style the account button flyout
• [x] Maybe use a TransitioningContentControl instead of the current TabControl for main content
• [ ] Use a different modal layout when user is already logged in (for email/password change, account deletion, etc)
• [ ] Figure out why modal animations trigger layout updates on the whole container
• [ ] Add confirmation messages after performing operations in modal (eg: display big red countdown after account deletion request)