Improve Docker-Compose Install Experience (#9781)

This PR updates the docker-compose installation documentation and env
sample to improve the setup experience.

- Updates the URLs for raw files to reference main branch, which is
likely where new users will be pulling from initially. This seems to be
the most straightforward option; assume that advanced users who want to
retrieve it from a particular tag will know to change the URL for their
scenario.
- Fixes an improperly stated curl command.
- Adds a note that the PGPASSWORD_SUPERUSER should be URL-safe. This is
required since the value is later concat into a PG_DATABASE_URL as a
URL, and expected to be in proper URL format. Touches on #8597.

---------

Co-authored-by: Félix Malfait <felix@twenty.com>
Co-authored-by: Félix Malfait <felix.malfait@gmail.com>

packages/twenty-docker/scripts/install.sh

@@ -90,12 +90,11 @@ else
 fi
 
 # Generate random strings for secrets
-echo "# === Randomly generated secret ===" >>.env
-echo "APP_SECRET=$(openssl rand -base64 32)" >>.env
+echo "# === Randomly generated secret ===" >> .env
+echo "APP_SECRET=$(openssl rand -base64 32)" >> .env
 
-# Issue with Postgres spilo?
-#echo "" >>.env
-#echo "PGPASSWORD_SUPERUSER=$(openssl rand -hex 16)" >>.env
+echo "" >> .env
+echo "PG_DATABASE_PASSWORD=$(openssl rand -hex 16)" >> .env
 
 echo -e "\t• .env configuration completed"