* Adapt dev env to run on a remote box
* webpack-dev-server ignores CLI arguments, so switched to environment
variables.
* Dynamically determine remote webpack host via APP_DOMAIN environment
variable, defined in application.yml.
* Setup content security policy to allow connecting to webpack on a
remote box, defined by APP_DOMAIN environment variable.
* Make Webpacker listen on 0.0.0.0
* Account for APP_DOMAIN port
* Add support for URI scheme and tests
* Fix a spec by disabling a Rubocop linter
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