* appservice: add and use matrix_homeserver_* vars
* appservice: use the new vars
* Apply suggestions from code review
Co-authored-by: Slavi Pantaleev <slavi@devture.com>
Co-authored-by: Slavi Pantaleev <slavi@devture.com>
Details here: https://docs.ansible.com/ansible/devel/porting_guides/porting_guide_6.html#id36
Basically:
```yaml
- name: Prior to 2.13
debug:
msg: '[1] + {{ [2] }}'
- name: 2.13 and forward
debug:
msg: '{{ [1] + [2] }}'
```
Interestingly, we had been using the new/safe syntax in lofs of places.
We were using the broken one in many others though. Hopefully all
instances were fixed by this patch.
