Improve Donate Button

[AristurtleDev]

Description

This PR adjusts the donate link in the navigation header to stand out more by presenting it as button style, right-aligning it within the navigation menu, and adding an effect on hover that makes the heart icon pulse.

Preview

donate_button_heart_pulse.mp4

Related Issues

This is in response to #74

[AristurtleDev]

@tomspilman regarding this PR, I've hit a bit of a snag due to docfx.

Since there's full control over the website part generated by 11ty, I can do what I need with the donate button as shown above. However, the documentation stuff generated by docfx dynamically builds the navigation bar through a JS script on page load. This means I can't override the template directly to place it right-justified like on the main page part.

However, within what I can do with docfx's templates, I can add it manually outside the script but it will be pushed all the way to the end, after the theme switch toggle.

If moving the donate button here is fine, I can make that adjustment and push it up, but it would need to be pushed here on both the main site and documentation sites to maintain consistency.