support Select All shortcut in settings fields

[Buckwich]

Problem you would like to solve

Ctrl-A / Edit > Select All should select all input if an input is focused in settings

Proposed solution

Add proper keyboardTrap and focus detection of inputs in modals (renedered in a portal) and enable the select-all tool.

A start was done in https://github.com/camunda/camunda-modeler/tree/5306_select-all-settings-input. It still has some issues with getting the right focus

Alternatives considered

• Don't support it

Additional context

• cf. fix(client/plugins): add keyboard interaction trap to all plugin modals #1819