The previous method was a bit more difficult for users to interact with as they needed to ensure the file was at a certain path in the built image. This change divorces the file from the built artifact, better aligning the nginx.conf.sigil handling with the rest of Dokku's monorepo support.
A side effect of this is now building proxy configurations does not require access to the built image.
Closes#5207
The default for an app is empty, meaning it will fallback to the global value (which defaults to true). This will allow users to properly override the global value, regardless of what it is.
This standardization makes it somewhat easier to read stacktraces as the command names are all uniform, so it will be slightly easier to scan trace output.
This enables the HSTS header by default when an SSL certificate is in use. HSTS options can also be managed via the nginx:set command, which also exposes the ability to disable HSTS for your application.
