Add Changedetection blueprint with Docker Compose and configuration files

- Introduced Docker Compose setup for Changedetection service, including volume configuration.
- Added logo for Changedetection.
- Created template.toml for Changedetection with default variables for configuration.

blueprints/changedetection/template.toml

@@ -0,0 +1,8 @@
+[variables]
+main_domain = "${domain}"
+
+[config]
+[[config.domains]]
+serviceName = "changedetection"
+port = 5000
+host = "${main_domain}"