[Projection tooling] Implement type database

[kotlarmilos]

This is the tracking issue for type database.

Tasks

• [Projection tooling] Provide basic API for TypeDatabase #2921
• [Projection tooling] Implement type database creation algorithm
  • [Projection tooling] Implement algorithm deciding whether a struct should be projected as class or struct #2886
• [Projection tooling] Provide mapping between TypeDecls, TypeSpecs and TypeDatabase entries #2924

[kotlarmilos]

#2889 moved to M2+.