Also delete several useless files Change-Id: I1b17e4eca17e69169002fc617180beb2ac83f67a
install, and requirements pages and redirect to the new sdk pages. Also update the "older sdks" doc to include all version-specific sdks. also update the robots file to disallow indexing of the old sdk docs.
BUG=1790234 Automated import of CL 149211