Add Appflowy as an example of Flutter application.

[dmitry-erin]

AppFlowy is an AI-powered secure workspace where users achieve more without losing control of their data. It allows to take notes, track to-dos, and manage projects in a secure, local-first workspace.

Description of changes

The app VM with Appflowy was added. AppFlowy is an AI-powered secure workspace where users achieve more without losing control of their data. It allows to take notes, track to-dos, and manage projects in a secure, local-first workspace.
Since Flutter apps require opengl, the hardware.opengl.enable option was set to true for the app VM. Additional checks for platform were added because the Appflowy supports only x86_64-linux.
The task id is SP-4362.

Checklist for things done

• Summary of the proposed changes in the PR description
• More detailed description in the commit message(s)
• Commits are squashed into relevant entities - avoid a lot of minimal dev time commits in the PR
• Contribution guidelines followed
• Ghaf documentation updated with the commit - https://tiiuae.github.io/ghaf/
• PR linked to architecture documentation and requirement(s) (ticket id)
• Test procedure described (or includes tests). Select one or more:
  • Tested on Lenovo X1 x86_64
  • Tested on Jetson Orin NX or AGX aarch64
  • Tested on Polarfire riscv64
• Author has run nix flake check --accept-flake-config and it passes
• All automatic Github Action checks pass - see actions
• Author has added reviewers and removed PR draft status

Testing

Build Ghaf image for Lenovo X1, run it. Enter menu, choose the Appflowy. The application must run. The user must be able to create new document/page, make notes, set covers and etc.

Needs to pass build

[vilvo]

Please cherry-pick/include these changes - vilvo@d67351d

[milva-unikie]

Tested on X1

• Test-automation passes
• Performance ok
• Apps launch from icons
• Appflowy is mostly working

Found the following issues in Appflowy:

• Text cursor is blinking in app even when the app is not active.
• Can not change data directory from welcome-page or from settings.
• Share-button does not work.
• There is a menu behind a question mark in bottom right corner. The options in the menu seem to do nothing.
• Most of the emojis are not shown correctly. Also characters in some languages are not shown correctly.
• Swedish does not work. Trying to change the language to svenska leads to an error Unable to load asset: "assets/translations/sv.json. I found no way to exit from this error message and even restarting the app does not work. Only way to close the error message was to restart the laptop. Every other language seems to work, I just accidentally found the one that did not.