docs: add tips and tricks page

[isabelroses]

Following up on #449.
This PR:

• Adds a guide on how to set up live reloading with Stylus, how to create a new userstyle with UserCSS on Stylus.
• Documents how to blur/censor text in preview screenshots (with Flow Circular font).
• Documents how to use SVGs as background-images.
• Documents how to replace images created with <img> tags.
• Adds installation and usage instructions for converting images to WebP (ideally temporary until Update to Rust native webp implementation catwalk#5 is done/resolved).

[isabelroses]

As a note, I'm unsure where to put a link to new documentation.
I was thinking either general recommendations or at the end of userstyles creation.

[uncenter]

Should we incorporate https://github.com/uncenter/ctp-userstyles/blob/docs-quick-tips/docs/quick-tips.md into this? Or add as a separate PR?

[isabelroses]

Should we incorporate https://github.com/uncenter/ctp-userstyles/blob/docs-quick-tips/docs/quick-tips.md into this? Or add as a separate PR?

Bring it into this PR. We may as well do it in one go.

old

[sgoudham]

I'd appreciate if you could add a   in between each ### block, similar to the https://github.com/catppuccin/userstyles/blob/main/docs/userstyle-creation.md

change has been accomplished

[uncenter]

Looks good to me. Better to merge now and we can iterate on it later than to keep it in this stage. I can make another PR maybe later this week to add more of the stuff in #449.