ADO SQL v2 sensor: add the possibility to edit/add channels after creation

1) ADO SQL v2 sensor: add the possibility to edit/add channels after creation and other usability issues

Problem: we use a single ADO SQL v2 sensor dedicated to monitor some values using ODBC regarding some counters in our ERP business system. We use KEY VALUE pair mode, basically a named channel for each row with its accompanying value. We need to add some new value to monitor sometimes. Apparently, the sensor doesn't support editing after creation (?). It's a pain to rebuild the sensor just to add a channel. Additionally, performance/impact wise, it's better to have a single query returning many rows, instead of building a different ADO SQL sensor per single channel.

2) Please allow to define a query (textarea) directly in the sensor instead that via external, it would be nice and would limit the user to the web interface.

thanks for any feedback and for considering this