Allow nginx overrides of "http" context, not just "server" context

[gilbertsoft]

Is your feature request related to a problem? Please describe.
Some configurations like the server directive for another website are possible at http context only but DDEV offers only includes for the server context.

Describe the solution you'd like
It would be nice to have the same feature as for the server context (files in .ddev/nginx/) available for the http context. This could be simply achieved by the line include /mnt/ddev_config/nginx/http/*.conf; after the last server block.

Ofc same would be nice for Apache too, but I never had to change the Apache configuration so far and I don't know the details of the available options there.

Describe alternatives you've considered
Alternative is currently to provide the full nginx configuration.

Additional context
This would be a quick solution for the issues #1850 and #1889 too.

[rfay]

Thanks!

[rfay]

Closing in favor of #2263 - That will allow much more user configuration of nginx, including multiple docroots/subsites.