Organize constraint system and value domain modules into dune libraries

[sim642]

This continues #1288.

Previously Analyses was a mix of constraint systems, analysis specifications and analysis result outputting. By splitting this module up, constraint systems and solvers can nicely be isolated.

The other big chunk at the bottom of goblint.lib dependency graph was all the various ValueDomain parts. All analyses indirectly depend on them due to the existence of the EvalValue query.
A couple of not-so-related modules also come along for now. We'll have to find a better place for those later.

This PR introduces new dune libraries:

1. goblint.constraint for (side-effecting) constraint systems.
2. goblint.solver for solvers.
3. goblint.cdomain.value for ValueDomain and all of its components.

TODO

• Gobview (Add goblint.constraint and goblint.solver dependencies gobview#36).