Safety checks + conservative mount defaults

Added some safety checks

• Check that ioc git repo is public before cloning (fixes indefinite hanging bug for non-public repos)
• Only source env.sh from ioc repo if it exists (removes env.sh requirement from ioc repo)
• Only mount the main e3 lab share on /epics. (This is likely to be the people want to use/change. They can add others as needed)

defaults/main.yml

@@ -53,8 +53,6 @@ ioc_prometheus_exporter_user: e3-exporter
 # e3 nfs mounts
 ioc_nfs_mountpoints:
   - { src: "e3-share-lab.cslab.esss.lu.se:/e3", path: "/epics"}
-  - { src: "e3-share-lab.cslab.esss.lu.se:/e3-dev", path: "/epics-dev"}
-  - { src: "e3-share-lab.cslab.esss.lu.se:/e3-test", path: "/epics-test"}
 
 # default epics share to use
 ioc_epics_root: /epics