Blender can initialize differente user script paths

[iLLiCiTiT]

Issue

Blender can have set only one BLENDER_USER_SCRIPTS which is already occupied by OpenPype implementation.

Changes

• blender install method also register plugins/scripts/addons from OPENPYPE_BLENDER_USER_SCRIPTS
• advantage is that it should be possible to register multiple paths

Warning

• this implementation is using "copy" of inner blender python module function so it may change over time
• tested only on Windows with my custom plugin (didn't find other plugin that would use BLENDER_USER_PATH)
• implemented only OpenPype 3 variant

Note

• OPENPYPE_BLENDER_USER_SCRIPTS was added with PR

Closes: #1050

[hound]

Do not use bare except:, it also catches unexpected events like memory errors, interrupts, system exit, and so on. Prefer except Exception:. If you're sure what you're doing, be explicit and write except BaseException:.
do not use bare 'except'

[hound]

Do not use bare except:, it also catches unexpected events like memory errors, interrupts, system exit, and so on. Prefer except Exception:. If you're sure what you're doing, be explicit and write except BaseException:.
do not use bare 'except'

[hound]

Do not use bare except:, it also catches unexpected events like memory errors, interrupts, system exit, and so on. Prefer except Exception:. If you're sure what you're doing, be explicit and write except BaseException:.
do not use bare 'except'

[mkolar]

@simonebarbieri could you please have a look if this works for you and give review?

[hound]

'load_scripts' is too complex (31)

[iLLiCiTiT]

Fixed addons set through the BLENDER_USER_SCRIPTS environment.