Switch from envrc → env format

Ref coop-cloud/abra#40

.env.sample

@@ -1,28 +1,28 @@
-export APP=selfoss
+APP=selfoss
 
-export DOMAIN=reader.example.com
+DOMAIN=reader.example.com
 ## Domain aliases
-#export EXTRA_DOMAINS=', `www.selfoss.example.com`'
-export LETS_ENCRYPT_ENV=production
+#EXTRA_DOMAINS=', `www.selfoss.example.com`'
+LETS_ENCRYPT_ENV=production
 
 # Selfoss options, see https://www.selfoss.aditu.de/#configuration
 
 # Options are sqlite, pgsql, mysql; currently sqlite and pgsql are supported
 # If you choose pgsql, uncomment the COMPOSE_FILE line
-export SELFOSS_DB_TYPE=sqlite
-#export COMPOSE_FILE="compose.yml:compose.postgres.yml"
+SELFOSS_DB_TYPE=sqlite
+#COMPOSE_FILE="compose.yml:compose.postgres.yml"
 
 # Set these two variables to enable authentication
-export SELFOSS_USERNAME=
-export SELFOSS_PASSWORD=
+SELFOSS_USERNAME=
+SELFOSS_PASSWORD=
 # The recommended /password hash script currently seems broken; use this instead:
 # 	http://www.passwordtool.hu/php5-password-hash-generator
 
 # Options are EMERGENCY, ALERT, CRITICAL, ERROR, WARNING, NOTICE, INFO, DEBUG, None
-export SELFOSS_LOGGER_LEVEL=ERROR
+SELFOSS_LOGGER_LEVEL=ERROR
 
-export ENTRYPOINT_CONF_VERSION=v7
-export DB_PASSWORD_VERSION=v1
+ENTRYPOINT_CONF_VERSION=v7
+DB_PASSWORD_VERSION=v1
 # Not required yet, see
 # 	https://git.autonomic.zone/compose-stacks/selfoss/issues/3
-#export SELFOSS_PASSWORD_VERSION=v1
+#SELFOSS_PASSWORD_VERSION=v1