Adding vscode debugging support

[MikeHingley22]

Adding supporting comments here :

• Added poetry support for this project - I added a mock Krita module, which means I don't need to have krita installed to debug and develop the python code.
• Identified that the intial bug was related to the data within the ini file - it had a colour value of black - whereas the code was expecting some RGB type value (0,0,0).
• Identified a slightly more efficient mechanism for supplying default values within code, and using chainmap to inject missing keys from defaults.
  • This has the advantage that empty settings files would still present a valid configuration.
  • The current "bad" colour data is read without crashing using this approach
• Added a vscode launch.json file, to allow debugging
• Additionally - some breaking lines were commented to allow easy testing (these were issues related mainly to hardcoded developer locations)

There are no tests for this code