feat(mouse): Add mouse move and scroll support (#2477)

* feat(mouse): Add mouse move and scroll support

    * Use Zephyr input subsystem for all pointers.
    * Input processors for modifying events, e.g. scaling, swapping
      codes, temporary (mouse) layers, etc.
    * Mouse move/scroll behaviors.
    * Infrastructure in place for physical pointer input devices.

* feat: Add input split support.

* docs: Add initial pointer docs.

---------

Co-authored-by: Cem Aksoylar <caksoylar@users.noreply.github.com>
Co-authored-by: Alexander Krikun <krikun98@gmail.com>
Co-authored-by: Robert U <urob@users.noreply.github.com>
Co-authored-by: Shawn Meier <ftc@users.noreply.github.com>
Co-authored-by: Chris Andreae <chris@andreae.gen.nz>
Co-authored-by: Anant Thazhemadam <47104651+thazhemadam@users.noreply.github.com>
Co-authored-by: Erik Tollerud <erik.tollerud@gmail.com>
Co-authored-by: Nicolas Munnich <98408764+Nick-Munnich@users.noreply.github.com>

app/core-coverage.yml

@@ -24,7 +24,7 @@ include:
     nickname: "display"
   - board: nice_nano_v2
     shield: kyria_left
-    cmake-args: "-DCONFIG_ZMK_MOUSE=y"
+    cmake-args: "-DCONFIG_ZMK_POINTING=y"
     nickname: "mouse"
   - board: sparkfun_pro_micro_rp2040
     shield: reviung41