Create proper "Release" job

I'm updating this ticket to collect requirements for a proper "release" job, which we do not currently have. In addition to uploading the artifacts (for which we do have automation), we can/should automate the following steps:

1. Update the version in http://appcast.couchbase.com/membasex.xml (for Mac update notifications)

2. Commit the manifest for the released build to the released/ subdirectory of github.com/couchbase/manifest

3. Create new Dockerfiles in github.com/couchbase/docker (create subdirectory, run generator script, commit results)

Other steps that we probably can't automate, but maybe:

1. Trigger automated Unofficial Docker builds on Docker Hub

2. Propose a change for the Official Docker image at https://github.com/docker-library/official-images

3. Update the Release Log wiki page at http://hub.internal.couchbase.com/confluence/display/CR/Couchbase+Server+Release+Log

4. Run AV check on Windows (and other?) installers