This argument was completely ignored by the wgpu renderer, and used only
for the `clip_mask` by the `tiny_skia` renderer. I believe creating a
new clip mask is correct.

This way it's possible to render offscreen without needing a surface.

`tiny_skia::Frame` was ignoring images in `Frame::paste`, making images
not show up when created in a `with_clip` context.

`wgpu::Frame` similarly did not pass through meshes in its paste method,
that may have been saved from a nested `with_clip` call.

* fix: load system fonts to usvg font_db, this will make rendering of text in svg that has it

* feat: add an example that renders svg that has text on it

* Initialize `fontdb` only once for `vector` images

* Remove `svg_text` example

* Set `fontdb` for `usvg::Options` in `tiny_skia::vector`

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Co-authored-by: Héctor Ramón Jiménez <hector@hecrj.dev>

This method should be able to leverage performance improvements in lyon's
`tessellate_rectangle` over `tessellate_path`.