Try link and focus styles

[carolinan]

Description
This PR adds text decoration thickness and underline offset for links.
This style is enqueued both in the editors and the front, using style.css and editor-style.css

It also adds a solid outline with 2px width on focus, to all focusable elements.
This style is only enqueued on the front, using style.css.
I did not add this style the editor, because it affected the way the blocks look when they are selected, and in my opinion, this can make the blocks more difficult to work with.

The PR Uses get_parent_theme_file_uri() so that the files are enqueued also for child themes. Please correct me if this is wrong!

For #72 #6

Screenshots

Testing Instructions

[github-actions]

The following accounts have interacted with this PR and/or linked issues. I will continue to update these lists as activity occurs. You can also manually ask me to refresh this list by adding the props-bot label.

If you're merging code through a pull request on GitHub, copy and paste the following into the bottom of the merge commit message.

Co-authored-by: carolinan <[email protected]>
Co-authored-by: juanfra <[email protected]>
Co-authored-by: justintadlock <[email protected]>
Co-authored-by: beafialho <[email protected]>

To understand the WordPress project's expectations around crediting contributors, please review the Contributor Attribution page in the Core Handbook.

[beafialho]

Could we add the hover state as well? Or maybe address that in another issue? I realised I haven't specified that in the Figma file.

[beafialho]

I have added the links hover states here, if it's helpful. Let me know if I missed any.

[carolinan]

If the hover styles can be added in theme.json, that would be better. If it doesn't work, we can use the css files.

[juanfra]

Thanks for working on this! I left a few comments.

[carolinan]

Eh no the contact pattern is not supposed to be on this branch o.o