settings: Add support for accent-color

[A6GibKm]

No description provided.

[A6GibKm]

The biggest change on Color was the addition of the From<OwnedValue> otherwise

error[E0277]: the trait bound `color::Color: From<OwnedValue>` is not satisfied
   --> src/desktop/settings.rs:178:14
    |
178 |         self.read::<Color>(APPEARANCE_NAMESPACE, ACCENT_COLOR_SCHEME_KEY)
    |              ^^^^ the trait `From<OwnedValue>` is not implemented for `color::Color`
    |
    = note: required for `OwnedValue` to implement `Into<color::Color>`
    = note: required for `color::Color` to implement `TryFrom<OwnedValue>`

For more information about this error, try `rustc --explain E0277`.
warning: `ashpd` (lib) generated 2 warnings

[bilelmoussaoui]

Thank you