Clean up & unify upgrade scripts

- Remove all unversioned upgrade steps
- Strictly compare versions as strings, fix regexps
- Unify variables across upgrade scripts
<docs> Update repos_base in puppet deployment guide

- Update the puppet deployment guide to use the milestone 4 release
  repos in the examples by default.
Merge pull request #5958 from detiber/puppetDeployGuide

<docs> Update repos_base in puppet deployment guide
Merge pull request #5949 from VojtechVitek/upgrade_scrips

Merged by openshift-bot
Add cucumber tests for Unified Push Server cartridge
Merge pull request #5925 from VojtechVitek/unified_push_server_tests

Merged by openshift-bot