* Add ISIS discovery and polling for iosxe devices
* remove ModuleModelObserver
* add php stan exclusions as they are already present for the base module
* change port_id to cached lookup
* Create model object instead of using arrays and set properties directly
* remove unneeded space...
* remove null from non nullable field
* revert to extending from ciscowlc rather than os
* remove OS module
* remove phpstan exclusions and fix errors
* add spacing...
* add spacing....
* add spacing
* again...
* Add tests
* Update Iosxe.php
* Update IsisAdjacency.php
* Create 2022_04_08_085504_isis_adjacencies_table_add_index.php
* Update db_schema.yaml
* Update iosxe_asr920.json
* Update Iosxe.php
* Update Iosxe.php
* Update junos_mx5t_isis.json
Co-authored-by: Tony Murray <murraytony@gmail.com>