[Feature]: dedicated option for timesteps as continuous seasons

[Rick-Methot-NOAA]

Describe the solution you would like.

Some aspects of current approaches to continuous seasons could be improved:

1. normal models have input in terms of year, season and year, month. It would be convenient if these input formats could be retained and internally converted to a continuous stream of time steps (i.e. no seasons within years).
2. the settlement time calculations depend upon input of month of settlement and calendar age at settlement. This does not work properly with continuous seasons. A desirable approach would allow for a quarterly model to have a spawner-recruitment relationship and for the recruits to settle XXX quarters after spawning.
3. the concept of calendar age becomes corrupted when doing continuous seasons, but this may not be fixable.

Describe alternatives you have considered

simply warn users that the feature is not available

Statistical validity, if applicable

NA

Describe if this is needed for a management application

perhaps

Additional context

No response