Removed host and port from pygeoapi configuration

[ricardogsilva]

This PR removes web application server initialization parameters from the pygeoapi configuration, specifically the server.bind section. This includes:

• server.bind.host
• server.bind.port

These now become initialization parameters, passed to pygeoapi serve. Included in this PR is a working implementation for all of:

• flask
• starlette
• django

pygeoapi serve now accepts two optional parameters:

• host - defaults to "127.0.0.1" - this is intentionally not set to "0.0.0.0" in order to prevent accidental exposure of private services.
• port - defaults to 5000

Related issue / discussion

• Fixes Remove server host and port from pygeoapi configuration #1523

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

[ricardogsilva]

Withdrawing this PR, as there seems to be appreciation for having these parameters in pygeoapi config