Support retrieving bindings by buildpacks

[arjun024]

Context

Some buildpacks may accept settings/credentials using bindings at build or runtime. A common example would be the host location and credential for an external service.

Issue request

Packit should provide a way for a buildpack to look up and retrieve these bindings.

Example Use case.

See the session handler buildpacks in this proposed PHP RFC. They expect their settings to be provided through a suitable binding.

Related links

https://paketo.io/docs/buildpacks/configuration/#bindings
https://github.com/paketo-buildpacks/rfcs/blob/main/accepted/0010-dependency-mappings.md
https://github.com/paketo-buildpacks/maven/tree/v3.2.1#bindings