Description of problem:

`--foreman-proxy-content-enable-docker false` should disable the container gateway feature but it does not.  ekohlvan@redhat.com suggests that this should be renamed with -enable-container to match Pulp's terminology.

How reproducible:

Easy

Is this issue a regression from an earlier version:

No

Steps to Reproduce:

run `satellite-installer --foreman-proxy-content-enable-docker false` on Capsule

Actual behavior:

the container gateway  is still enabled

Expected behavior:
the container gateway  should be disabled

Business Impact / Additional info:

This is causing a great confusion when upgrading from 6.14 to 6.15 which migrates the container gateway plugin from sqlite to postgres.