Remove all 2.3 specific datasource code.

Unfortunately, there is no elegant way to commit the datasource changes because the datasource file name must be different in the end (which will make Git see the changes as file removal/addition). So we drop everything in this commit and add a 2.2.x compatible datasource shortly after.
Add a 2.2.x compatible datasource.

Please note that param output must be different (using dash instead of dots to build the parameter name).
Add about function to the extension driver.
Require DataSource class (since we extend it).
Rename execute() function: __trigger() is needed.
Change author credit.
Correct version number.