default deployment is now to filesystem on cloudfronted developers-origin,
with profile for deploying to artifactory;
docs updated to show same (new) preferred download URLs

(cherrypicked from master)
fix docs build for the case where we are building docs for the root
(backport cherry-pick from master)
brooklyn-dist should be in a directory named for the current version, not hanging off the root
(backport cherry-pick from master)
update download links and instructions to reflect dist archive structure,
and be a little bit clearer in general
(backport cherry-picked from master)
pom updated to support deployment to sonatype
(backport cherry-pick from master)
remove unused sections of pom
(backport cherry-pick from master)
reorder profiles in pom (no changes)
(backport cherry-pick from master)
created bogus empty java files for examples, so that javadoc artifact is created, and build is not rejected by maven central!
(cherry-picked from master)
doc links updated to point at sonatype and maven central (in addition to cloudsoft)
(backport cherrypicked from master)
removed use of properties for deploymentManagement, now deployment management is just in profiles
(backport cherrypicked from master)