Allow other python packages to extend rocolib

Other developers should be able to create Component, Composable, and Port subclasses, and component definitions (via library .py, library .yaml, or builder files), and release them together as an integrated package that plays nice with the rocolib api (without needing to MR to the main rocolib repo).

• Component / Composable / Port subclasses
• Component library definitions
• utils

added enhancementcore label

changed milestone to %0.4.x

https://packaging.python.org/en/latest/guides/creating-and-discovering-plugins/

mentioned in issue #31 (closed)

marked this issue as related to #31 (closed)

mentioned in issue #34

Maybe change name to rocoapi to distinguish it from a library

marked the checklist item Component library definitions as completed

changed the description