[#65] services: Fix docker-compose warnings

There were multiple warning like this one.
```
WARN[0000] /secret/services/rest_gate/docker-compose.yml: `version` is obsolete
```

According to docker-compose spec, the parameter is indeed purely informative:
https://github.com/compose-spec/compose-spec/blob/master/spec.md#version-and-name-top-level-elements

Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>

services/grafana/docker-compose.yml

@@ -1,4 +1,3 @@
-version: '2.4'
 services:
   grafana:
     image: ${GRAFANA_IMAGE}:${GRAFANA_VERSION}