Add support for custom Docker registries (#275)

* Add support for custom Docker registries

This allows a user to set the `CONTAINER_REGISTRY` environment variable
which can be used in place of the default of ghcr.io if a customer would
like to mirror our image so they can self host behind any proxies or other
custom network stack.

* Add details to README about a custom docker registry

Merge pull request #235 from github/add-bb-commands

Add Bitbucket commands

Add --include-from option to GitHub forecast (#220)

Merge pull request #209 from github/no-host-network

Add option to disable the use of host network

Merge pull request #141 from github/bamboo-doc

AWS Code Deploy doc update

Merge pull request #138 from github/edit

Bamboo docs last update

Adds Bamboo commands (#102)

* Add Bamboo audit command

* Add Bamboo dry-run commands

* Add Bamboo migrate commands

* Wire things up

* lint

* Fix typo

Merge pull request #111 from mario-campos/main

Use host's network stack, not container's.

Build Apple arm64 binary (#106)

* Update ci.yml

* add rid

Update configure command to support configuring feature flags (#96)

* Update configure command to support configuring feature flags

This uses the changes from github/valet#5879 to fetch available flags
via the list-features --json flag. It parses out the possible env vars
and walks the customer through setting any feature flags they desire.

If there are any issues getting the available feature flags JSON, we
don't ask the customer to configure feature flags, as it won't cause any
breaking issues and we don't want to break the configure command.

* Move feature configuration to its own flag

* Add unit tests

* Undo changes to ConfigurationServiceTests

* Code review fixes