doc: add note about web app building/transfer
doc: add note about web app building/transfer

SignalK/signalk-server-node,SignalK/signalk-server-node,SignalK/signalk-server-node,webmasterkai/signalk-server-node,webmasterkai/signalk-server-node,webmasterkai/signalk-server-node,SignalK/signalk-server-node