Added API for fetching external database, removed parameters structure,

.env.example

@@ -53,6 +53,14 @@ SPOOLMAN_PORT=7912
 # Default: FALSE
 #SPOOLMAN_METRICS_ENABLED=TRUE
 
+# Collect items (filaments, materials, etc.) from an external database
+# Set this to a URL of an external database. Set to an empty string to disable
+# Default: https://donkie.github.io/SpoolmanDB/
+#EXTERNAL_DB_URL=https://myhost.com/spoolmandb/
+# Sync interval in seconds, set to 0 to disable automatic sync. It will only sync on start-up then.
+# Default: 3600
+#EXTERNAL_DB_SYNC_INTERVAL=3600
+
 # Enable debug mode
 # If enabled, the client will accept requests from any host
 # This can be useful when developing, but is also a security risk