[Feature] 'What's New'

[ryanraposo]

Generally, a great 'What's New' page would:

• Appear once on version updates.
• Provide useful information.
• Include an option to disable or throttle (major, minor, patch) to avoid being annoying.

Being early in development, and especially with the color picker update around the corner, priority is even higher!

We really want existing users who maybe haven't opened CodeUI in a while to notice :)

(Big thank you to @alefragnani! His beautiful 'What's New' page for the Bookmarks extension inspired the idea, and his extra work made this easy for all of us!)