Revise tmir sponsorship page

[vcarl]

Current sponsorship page is too complex, with too many options presented. It doesn't do a good job of selling why the podcast exists, and leaves it murky as to who the audience is and why they would be of interest to a sponsor.

This month in react intends to be a low cadence, high signal source of knowledge for professional react developers with 3 to 5 years of experience. It allows them to be the most up-to-date person in their office, which means that the actual reach of the podcast is substantially larger than its subscriber base