Generate state skeleton code from configuration

[alex-mitrevski]

In order to make it easier to start working on a state machine, it would be helpful to generate skeleton code for states specified in a state machine configuration file. There are two cases that need to be considered here however:

• if a specified state exists (e.g. it's already implemented in mdr_behaviours), there is no need to generate code
• if a state does not exist, the skeleton code for it should be generated (by default, the code could be generated at the path of the configuration file, although it would be best if the code is generated as part of the module specified in the configuration file)