GridModel should have an option to persist the last "expandAll"/"collapseAll" choice and default to that state on initial rendering

[febbraiod]

This is a feature requested multiple times by a client. This could be first step to a more comprehensive persistence of node open/close state.

[amcclain]

Yes agree this is a real gap - would be a good one to close.

We should review how ExtJs handles expand/collapse state and APIs to see if there is any inspiration to be had there. I've always felt like they had a better story around it than we have been able to replicate...so far

[amcclain]

See also #1844

[amcclain]

Let's update this ticket to cover a more comprehensive solution around expand/collapse state + defaults w/o needing to use agOptions, including support for levels