Remove ovos core dependency

[NeonDaniel]

Description

Refactor package to import from ovos-workshop and ovos-utils to remove mycrfot imports

Issues

Relates to #469

Other Notes

ovos-core is still listed as a test dependency as some tests are failing without it. Failures appear to be related to configuration handling, but are not immediately resolvable so this will be left to a future PR, possibly after some of the configuration marked for deprecation is actually deprecated

[mikejgray]

Found a few more doing some testing:

neon_utils.validator_utils:

# from mycroft.skills.core import MycroftSkill
from ovos_workshop.skills.mycroft_skill import MycroftSkill

neon_utils.skills.common_play_skill:

# from mycroft.skills.audioservice import AudioService
from ovos_utils.skills.audioservice import OCPInterface as AudioService

neon_utils.skills.skill_gui:

# from mycroft.enclosure.gui import SkillGUI as _SkillGUI
from ovos_workshop.skills.base import SkillGUI as _SkillGUI