Add hot-reload option to docker entrypoint

[webb-ben]

Overview

Adds hot reload option to docker entrypoint. Thereby fully enabling the function of the Admin API in the Docker deployment of pygeoapi

Related Issue / discussion

#1753
#1636

Additional information

This is not a complete implementation, but enough for someone to start developing a pygeoapi-ui of the base docker image.

Dependency policy (RFC2)

• I have ensured that this PR meets RFC2 requirements

Updates to public demo

• I have ensured that breaking changes to the pygeoapi master demo server have been addressed
  • https://github.com/geopython/demo.pygeoapi.io/blob/master/services/pygeoapi_master/local.config.yml

Contributions and licensing

(as per https://github.com/geopython/pygeoapi/blob/master/CONTRIBUTING.md#contributions-and-licensing)

• I'd like to contribute [feature X|bugfix Y|docs|something else] to pygeoapi. I confirm that my contributions to pygeoapi will be compatible with the pygeoapi license guidelines at the time of contribution
• I have already previously agreed to the pygeoapi Contributions and Licensing Guidelines

[totycro]

Are you sure this touch is actually executed?
As far as I understand it, exec gunicorn replaces the bash process with gunicorn and thus stops any further execution of the script, or is this somehow different here?