Enable specifying a dependency while staying agnostic of its dependencies

[keyboardDrummer]

If there's a chain of Dafny library dependencies, where a Dafny application or library A, depends on a library B, which depends on a library C, then it should be possible for A to declare its dependency on B without having to know about C.

How

• Enable the --library option to take a Dafny project file
• If --library is called with the exact same Dafny project multiple times, either directly or indirectly through a dependency, then those are deduplicated. If two arguments of --library are not exactly the same but contain root level modules with the same name, then a compilation error occurs.

Prerequisites

• Dafny project files: Enable configuring Dafny options through a project file #2907