.github: move repo labels management to probot/settings

.github/labels.yml

----
-# Default GitHub labels
-- color: d73a4a
-  name: bug
-  description: Something isn't working
-- color: cfd3d7
-  name: duplicate
-  description: This issue or pull request already exists
-- color: a2eeef
-  name: enhancement
-  description: New feature or request
-- color: 7057ff
-  name: good first issue
-  description: Good for newcomers
-- color: 008672
-  name: help wanted
-  description: Extra attention is needed
-- color: e4e669
-  name: invalid
-  description: This doesn't seem right
-- color: d876e3
-  name: question
-  description: Further information is requested
-- color: ffffff
-  name: wontfix
-  description: This will not be worked on
-
-# Labels specific to cloudalchemy
-- color: 0366d6
-  name: area/docs
-  description: Improvements or additions to documentation
-- color: 0366d6
-  name: area/tests
-  description: Everything related to molecule tests and linters
-- color: 0366d6
-  name: area/automation
-  description: Bots, bots everywhere
-- color: 0366d6
-  name: area/vars
-  description: Ansible variables used in role
-- color: 0366d6
-  name: area/tasks
-  description: Logic behind ansible role
-- color: 0366d6
-  name: area/jinja
-  description: Templates

.github/workflows/labels.yml

----
-name: Sync labels in the declarative way
-on:
-  push:
-    branches:
-      - master
-jobs:
-  build:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@1.0.0
-      - uses: micnncim/action-label-syncer@v0.3.1
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-          GITHUB_REPOSITORY: ${{ github.repository }}
-        with:
-          manifest: .github/labels.yml