Remove `docker-compose-portainer.yml` file

[Raruto]

Probably the file was created for the following reason (i.e. using a previous docker compose version, < 3):

g3w-suite-docker/docker-compose-portainer.yml

Lines 1 to 4 in e435dcc

	# docker-compose file for Portainer(https://www.portainer.io)
	# A the moment Portainer work only with version "2"
	version: "2"

g3w-suite-docker/docker-compose.yml

Line 1 in e435dcc

version: "3"

Anyway, since version 2.1.1 this requirement is no longer be necessary.

[Raruto]

if so, remember to update the project README.md and official documentation about it (ie. removing the portainer section):

• https://g3w-suite.readthedocs.io/en/latest/docker.html#portainer

• g3w-suite-docker/README.md

  Lines 199 to 208 in e435dcc

  	## Portainer
  	Portainer(https://www.portainer.io) is a software for build and manage Docker environments in an easy and graphical way.
  	For Portainer use `docker-compose-portainer.yml` file and in plus of env vars before, set the follow mandatory env vars:
  	* G3WSUITE_DOCKER_INSTALL_DIR: host directory where this code is.
  	* PG_PUBLIC_PORT: host port to map Docker PostgreSql default port (5432).
  	* WEBGIS_HTTP_PORT: host port to map Docker Nginx port (8080).
  	* WEBGIS_HTTPS_PORT: host port to map Docker Nginx port (443).