Extend the SubView's sortField attribute to allow sorting by multiple fields

[maxpatiiuk]

Like isCurrent,-timestampCreated

Description of the sortField attribute: https://github.com/specify/specify7/wiki/Form-System#:~:text=sortField%20(string%2C%20optional%2C%20case%2Dinsensitive)

[specifysoftware]

This issue has been mentioned on Specify Community Forum. There might be relevant details there:

https://discourse.specifysoftware.org/t/order-subviews-by-multiple-related-fields/2155/1

[bronwyncombs]

Philippe @ IRD add support for this on discourse

For some loans we may have dozens or even hundreds of loan preparations, so my colleagues asked for sorting default grid view by Collectors, and Collector number.

Since Specify 7.7 I read that subviews accept one sort field argument sortField=${fieldName}.

This is how I’d like to initialize the subview:
<cell type="subview" viewname="LoanItems_Aublet3_Form" id="10" name="loanPreparations" defaulttype="table" initialize="sortField=preparation.collectionObject.collectingevent.collectors,preparation.collectionObject.collectingevent.stationFieldNumber" colspan="17" rows="4"/>