Config flow for elkm1 (#33297)

* Config flow for elkm1

* As entity ids can now be changed, the “alarm_control_panel”
attribute “changed_by_entity_id” is now “changed_by_keypad”
and will show the name of the Elk keypad instead of the entity id.

* An auto configure mode has been introduced which avoids the
need to setup the complex include and exclude filters.  This
functionality still exists when configuring from yaml for power
users who want more control over which entities elkm1 generates.

* restore _has_all_unique_prefixes

* preserve legacy behavior of creating alarm_control_panels that have no linked keypads when auto_configure is False

* unroll loop