cylc install: parse and cache cylc play options

[oliver-sanders]

See also the rose suite-run migration proposal.

Consider modifying cylc install to accept arguments for cylc play. These arguments would be saved in a user-facing file in the run dir which would be loaded by a subsequent cylc play operation.

Example:

Under this proposal the following "regular" usage:

$ cylc install
$ cylc play <flow> -s foo=bar

Would be equivalent to this:

$ cylc install -s foo=bar
$ cylc play <flow>

Use Case:

The anticipated use case is for situations when flows are installed but then not run until a later date.

Related Work:

Perhaps this should be considered in tandem with a Cylc file for defining workflow inputs #3900.