rose app-upgrade: better output macro name
Merge pull request #1327 from benfitzpatrick/rose-app-upgrade.underscore_macro_output

rose app-upgrade: better output macro name
Cylc 6 updates

Rephrase *cycle time* to *cycle point*.
Suite log/job/ and work/ restructure.
ROSE_TASK_LOG_DIR: new environment varaible

Alias of CYLC_TASK_LOG_ROOT.