Refactor module builder and fix issue 41

[mrakitaTT]

Fixes #41 by adding -vhlo-to-version pass before -vhlo-legalize-to-stablehlo in order to update VHLO to latest version. That converts v1 ops to v2 ops, and then -vhlo-legalize-to-stablehlo successfully converts vhlo.dot_general_v2.

Refactored module builder in the process:

• Reorganized code into multiple functions
• Moved dialects and passes registration into constructor so it is done only once and not during every compile
• Changed module builder to return PJRT status instead of throwing errors, previous error messages are now logged and status is reported from api_impl.cc::ClientInstance::Compile function
• Removed unnecessary includes and sorted them

[mrakitaTT]

FYI @vladimirjovanovicTT

[kmitrovicTT]

So neat and readable. Kudos!