mariadb client option --script-dir

If the mysql client starts a script (regardsless if via < or source funtion),
and the script invokes other scripts (only scriptnames without paths),
the client will search scripts only in the working dir of the mysql/mariadb client.

Add an option:

--script-dir=<directorypath>

which set the path, where scripts will be searched via source command in a sql-scripts

Default is still mysql client path