2021-October-26 - Prerelease - 2.6.437

Simplify: Out of date engine check/update dialog (#9733)

* Refactor: update 'showOutOfDate' component to actually show the out of date dialog

* Simplify: use 'JEditorPaneWithClickableLinks'

* Simpliy: remove code that sets max panel size

A dialog cannot be resized, setting the max size has no effect.

* Simplify the warning text in the out-of-date engine dialog

* Further simplify out-of-date dialog text

Remove the mention of the current engine version, while an interesting
detail, it is not critical to have (#lessIsMore).

* Further simplify release notes dialog, combine editor pane dialogs

* Update out-of-date dialog, convert 'download link' to be a button.

Instead of a dialog with links for download, release notes, and an 'ok' button;
the dialog now has the release notes link and a button to 'download now'
and a 'remind me later' button.

* Refactor: wire the 'LatestVersionResponse' object to OutOfDateDialog instead of just latest version

* Obtain release notes and download URLs from server

Instead of the game client knowing the download URL and releae notes URL
of the latest release, the server will instead tell the client these two
URLs as part of the 'latest engine check' response payload.