Adds states for secondary and destructive buttons

[nataliafitzgerald]

Adds states for secondary and destructive buttons (as built in Capital Framework)

Additions

• Add secondary button states
• Add destructive button and states

Removals

-

Changes

• Remove disabled from "Animation" code

Testing

-

Review

• @marteki @Scotchester

Preview this PR without the whitespace changes

Screenshots

Notes

-

Todos

-

Checklist

• [ ] Changes are limited to a single goal (no scope creep)
• [ ] Code can be automatically merged (no conflicts)
• [ ] Code follows the standards laid out in the front end playbook
• [ ] Passes all existing automated tests
• [ ] New functions include new tests
• [ ] New functions are documented (with a description, list of inputs, and expected output)
• [ ] Placeholder code is flagged
• [ ] Visually tested in supported browsers and devices
• [ ] Project documentation has been updated (including the "Unreleased" section of the CHANGELOG)

[marteki]

Out of scope for this PR, but noting while I'm paying attention: there's the whole thing about destructive actions paired with primary button, where we refer to a "destructive action button link."

Button links aren't a thing that's mentioned anywhere else on the page, and it feels weird to just refer to it without more guidance about how to use them (and maybe more importantly, how not to use them).

[nataliafitzgerald]

@marteki I updated the page and placed the "States" section heading back in.

[jimmynotjim]

Related note, we also use button links in expandables, but then they don't have the underline, just the text and icon.