Reformat `{{ { ... }[engine] }}` dict-in-Jinja-expressions across
bot/bridge role defaults for consistent indentation (tabs -> spaces).
Also: fix a missing space in a Jinja `+` expression in matrix-static-files,
and fix indentation in the caddy2-in-container example.

The original PR also renamed `galaxy/<role>` role references to just
`<role>` in setup.yml and jitsi_jvb.yml; those were dropped here because
Ansible does not recurse into subdirectories of `roles/` by default and
no `roles_path` is configured in ansible.cfg, so the rename would break
role resolution.

Co-Authored-By: Slavi Pantaleev <slavi@devture.com>