cherrypick Change-Id: I19d2be00c807b6cbdab357b32a7dd13f98a5433e

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