docs: update to adt 8.0.1;
delete ADT archive page, put a redirect in its place;
update tools release notes and sys reqs to require ant 1.8
Change-Id: Id039d81953452d8f7cefc0c4d61e7d9ead575541
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.
move upgrading doc into a new guide for "updating" with
the new manager tools and remove the previous updating doc
from the dev guide. set up preliminary download page and guide
for installing the full SDK. add the requirements doc in sdk/
for all general purposes. revise the download 'thank you'
message.
bug: 2160782
