* com.noccy.pdo: Implemented reflection for PDO databases,
tables and columns. Reflectors for MySQL and Sqlite.
* com.noccy.pdo: Added pdo:inspect command.
* com.noccy.docker: Added basic stack management and commands.
* com.noccy.docker: Moved commands to dedicated namespace.
* Environment: readConfig and writeConfig helper added, with
a flag to use the global config dir ~/.config/spark.
* PDO shell improvements: .query command, -r and --db on command
line to read commands from file or preselect database.
* Updated build scripts and readme