Create an option to specify Xpress calls

[simonfernandes]

We need an option when setting up a call that will specify proposals in the call should be managed a different way (via the new Xpress management page).

Details need finalising but so far we have discussed having a simple checkbox. We need to consider whether the checkbox itself should be hidden behind a feature flag (i.e. not visible to other facilities). This may change how we word the option (e.g. "Xpress" vs something more generic).

[bashanlam]

@simonfernandes @deepaksftc @srconway @bolmsten @martin-trajanovski My proposed changes to address this issue are as follows. Any comment?

1. Add new column route to call table to identify "Xpress" proposal
2. Modify the 'Create new call' and 'Update the call' pages to accommodate the new column. The fields displayed on these pages for the new column should be conditional based on whether the Xpress feature flag (FeatureId.STFC_XPRESS_MANAGEMENT) is enabled

[srconway]

Sounds good to me. As I mentioned I think it would make sense to give the column a generic name - "Route"? where we add 'Xpress' as the data rather than an Xpress boolean column. Not sure if that's what you were planning anyway.

[simonfernandes]

Sprint planning notes:

Per Fredrik's suggestion to detect an Xpress proposal through its workflow, we will need to consider the workflow as part of this in #1109