Raising instead of returning error responses to rollback potentially partially committed transactions

Moving new symlinks into the pre-existing env dir (if exists) to preserve the pre-existing links (specifically the 'default' one)

Corrected moving the recommended version to the front of the list and properly sorted the flattened installed versions list by the version names to put the most recent at the top

Fixing a logic error in get_version by simply calling get_versions and returning the recommended version

PIPELINE TESTING: Playing with shared/workspaces testing

See merge request !1614