32 add namespace structure in the PlantUML result

[lucsorel]

The main feature added by this PR is to add this block at the beginning of the file so that data structures are displayed as grouped by their module structure:

@startuml py2puml.domain
namespace py2puml.domain {
  namespace package {}
  namespace umlclass {}
  namespace umlitem {}
  namespace umlenum {}
  namespace umlrelation {}
}
' ...
@enduml

Other features included:

• homogenization of the way types are displayed in module inspection (dataclasses, enums, named tuples, etc.) and AST parsing (class constructors)
• handling of forward references
• deduplication of similar composition relationships

[lucsorel]

@jjerphan @doyou89 @jonykalavera would you be interested in reviewing (even partially) this pull request, if you please?

I know it is a heavy one 😬 I fixed a couple of typing things while writing this contribution.

An external view is always interesting

[jjerphan]

Hi @lucsorel, as a user, I like this feature. 👍

As another project's maintainers and as a reviewer, I unfortunately have zero bandwidth to review it. 😕

[lucsorel]

Hi @lucsorel, as a user, I like this feature. +1

As another project's maintainers and as a reviewer, I unfortunately have zero bandwidth to review it. confused

Thanks for the response, I totally understand 👍