Hoist dialog

[cnrudd]

WIP.
This PR is for Hoist React ticket #861 .
This hoistDialog branch should be run with the new hoistDialog branch in toolbox. See toolbox PR 311.

This new Dialog component makes draggable an option on dialogs.
If a dialog is draggable, it opens centered with no mask behind it.

The component is a WIP. More work needs to be done to be sure that the following use cases work:
Content with forms with autofocus fields and buttons, select and datepicker fields which when the select menu or datepicker popup close on escape and enter, the dialog does not close.

Also needed:

1. support for a draggable popup whose last position is remembered - API does not yet support
2. support for a draggable popup that is resizable (with size remembered). - API does not yet support

Would also be good to rewrite all XH.messages to use this new dialog. That would be a good collection of tests.

Hoist P/R Checklist

Review and check off the below. Items that do not apply can also be checked off to indicate they
have been considered. If unclear if a step is relevant, please leave unchecked and note in comments.

• Up to date with develop branch as of last change.
• Ready for review (or open as a draft PR / add wip label).
• Added CHANGELOG entry (or N/A)
• Reviewed for breaking changes (add breaking-change label + CHANGELOG if so, or N/A)
• Updated doc comments / prop-types (or N/A)
• Reviewed and tested on Mobile (or N/A)
• Created Toolbox branch / PR (link provided here, or N/A)

Pull request reviewers: when merging this P/R, please consider using a squash commit to
collapse multiple intermediate commits into a single commit representing the overall feature
change. This helps keep the commit log clean and easy to scan across releases. PRs containing a
single commit should be rebased when possible.

[lbwexler]

Colin and I are now working together on this in earnest. Looking great!

[cnrudd]

Closing this PR. Development of a Hoist Dialog has moved to a new branch hoistDialogModel in which most config options are model config options, not props. I will open a new PR for that branch.