Add platform image_processing.qrcode

[zhujisheng]

Description:

Add platform image_processing.qrcode

Related issue (if applicable):

Pull request in home-assistant.io with documentation (if applicable): home-assistant/home-assistant.io#8208

Example entry for configuration.yaml (if applicable):

# Example configuration.yaml entry
image_processing:
  - platform: qrcode
    source:
      - entity_id: camera.door

Checklist:

• The code change is tested and works locally.
• Local tests pass with tox. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated in home-assistant.io

If the code communicates with devices, web services, or third-party tools:

• New dependencies have been added to the REQUIREMENTS variable (example).
• New dependencies are only imported inside functions that use them (example).
• New or updated dependencies have been added to requirements_all.txt by running script/gen_requirements_all.py.
• New files were added to .coveragerc.

If the code does not interact with devices:

• Tests have been added to verify that the new code works.

[pvizeli]

Thanks