Billboard updates and additions

[Gluzman]

Improving and broadening design of billboard component sections for home page:

• announcement billboards
• evergreen billboards

after seeing how tbtc website is being used, these billboards add more flexibility and differentiation for specific use-cases about displaying information for audiences.

[Gluzman]

*needs review by @AmandaCassatt @creckhow @mhluongo — do these solve for having more flexibility in messaging? any other thoughts?

[mhluongo]

These are great.