wayland: add cursor_shape_v1 support

[kchibisov]

--

The protocol is dead simple and requiring a full rendering impl sounds overkill for it, given
that compositors can opt-in into this protocol, when they can handle the cursor themes.

Tested that it only reaches the compositor with YaLTeR/niri#32 , but the actual rendering is not done, and only default cursor is properly rendered.

Testing client https://github.com/Smithay/client-toolkit/blob/master/examples/themed_window.rs (press Shift + n to cycle icons).

[codecov-commenter]

Codecov Report

Attention: 165 lines in your changes are missing coverage. Please review.

Comparison is base (74ef59a) 22.71% compared to head (16d0ba3) 22.58%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1154      +/-   ##
==========================================
- Coverage   22.71%   22.58%   -0.14%     
==========================================
  Files         144      146       +2     
  Lines       23366    23533     +167     
==========================================
+ Hits         5308     5314       +6     
- Misses      18058    18219     +161     

Flag	Coverage Δ
wlcs-buffer	19.48% <2.92%> (-0.13%)	⬇️
wlcs-core	19.13% <2.92%> (-0.13%)	⬇️
wlcs-output	7.98% <2.92%> (-0.05%)	⬇️
wlcs-pointer-input	21.37% <3.50%> (-0.08%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
anvil/src/drawing.rs	41.81% <100.00%> (ø)
anvil/src/state.rs	36.81% <100.00%> (ø)
src/input/pointer/cursor_image.rs	100.00% <100.00%> (ø)
src/input/pointer/mod.rs	34.36% <100.00%> (ø)
src/wayland/tablet_manager/mod.rs	8.19% <ø> (ø)
src/wayland/tablet_manager/tablet_tool.rs	0.00% <ø> (ø)
wlcs_anvil/src/main_loop.rs	69.79% <0.00%> (ø)
src/wayland/cursor_shape.rs	0.00% <0.00%> (ø)

... and 1 file with indirect coverage changes

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[Drakulix]

Looks good to me.