[DEV-2022] SEER metadata recommendations

@mwhansen cr?

The recommendations are here: https://docs.google.com/a/rover.com/spreadsheets/d/1hnZzXsxCgHtsFnTNKtZOSqQhb0P6QuhzMXV3SE1UcKI/edit#gid=1729883536

There's a list of pages that Will wants not indexed; I've passed those along to Eric so he can include them in the sitemap ticket, if he has time.