Add support for custom modes and modelines. (#2479)

* Implement custom modes and modelines

Co-authored-by: ToxicMushroom <32853531+ToxicMushroom@users.noreply.github.com>

* fixes

* refactor mode and modeline kdl parsers.

* add IPC parse checks

* refactor: address feedback

* fix: add missing > 0 refresh rate check

* move things around

* fixes

* wiki fixes

---------

Co-authored-by: Christian Meissl <meissl.christian@gmail.com>
Co-authored-by: Ivan Molodetskikh <yalterz@gmail.com>

src/backend/winit.rs

@@ -83,6 +83,7 @@ impl Winit {
                     is_preferred: true,
                 }],
                 current_mode: Some(0),
+                is_custom_mode: true,
                 vrr_supported: false,
                 vrr_enabled: false,
                 logical: Some(logical_output(&output)),