Migrate configuration file from SharedPreferences package to YAML

[brainwo]

I have done a small research that led the decision to pick YAML.

The criteria I was looking for is that the configuration is language is that it must has a Dart library, not difficult to write, and is self-documented. The self documented part is basically what schema is for.

As someone whose edit their configuration file everyday, I find it's often annoying to go back and forth to check a manual for some program just to change a value in the configuration file, hence why I need it to be self-documented.

Alacritty seems to be the only program I use to support schema out of the box, their schema is listed on https://www.schemastore.org/json/ which picked up by my extension. I might consider adding my schema there if there is a possibility.

Here is comparison of popular configuration languages based on my limited time of researching them:

Name	LSP support	Schema	Additional features
YAML	Yes	Yes	Compatible with JSON
JSON	Yes	Yes	-
TOML	Yes(?)	Limited*	-
Pkl	Not ready	-	-
RON	-	-	-

* IntelliJ TOML plugin doesn't seems to support JSON Schema. However there are schema support for VS Code and coc.nvim.

While JSON comes for free in Dart. I find YAML is better suited since it's also compatible with JSON. Opening the possibility to use YAML/JSON based on user's preferences.

If there is any suggestion for a better language, leave a comment so I might consider it. Do keep in mind I will only keep one language at a time to be supported.

[brainwo]

Looks like I need to use this https://pub.dev/packages/xdg_directories