rose suite-log-view: use cylc suite runtime db.

Instead of parsing the log.
rose suite-hook: get job hosts from cylc suite db.

Instead of `cylc get-config`.
rose slv = rose suite-log-view
Merge branch 'master' into cylc.db
Merge branch 'master' into cylc.db
Merge branch 'master' into cylc.db
rose suite-hook: get signal from cylc-suite.db.
Merge branch 'master' into cylc.db
Merge pull request #477 from matthewrmshin/cylc.db

rose suite-log-view/suite-hook: use cylc-suite.db