fix: use LOG_LEVEL to set server log severity (#4937)

.env.sample

@@ -139,6 +139,10 @@ MAXIMUM_IMPORT_SIZE=5120000
 # requests and this ends up being duplicative
 DEBUG=http
 
+# Configure lowest severity level for server logs. Should be one of
+# error, warn, info, http, verbose, debug and silly
+LOG_LEVEL=info
+
 # For a complete Slack integration with search and posting to channels the
 # following configs are also needed, some more details
 # => https://wiki.generaloutline.com/share/be25efd1-b3ef-4450-b8e5-c4a4fc11e02a