Add ability to sponsor the library with tiers

[wesharper]

Describe the feature in detail (code, mocks, or screenshots encouraged)

Formkit's sponsor page is well made and the tiers, especially with the ability to put sponsor details on the docs page hopefully make it easier to get buy-in from companies.

What type of pull request would this be?

Other

Provide relevant links or additional information.

No response

[huntabyte]

Hey @wesharper, appreciate this! We'll work on an action plan for this!