Get rid of categories

[jecisc]

With the PR we are getting rid of categories in Hermes and are basing everything on packages and tags.

This introduces the v3 of the export format.

In some places I had to introduce different code for P10 and P12 but once P12 will be the minimal Pharo supported for this project we will be able to remove all of this.

I also used the class builder to build the traits.

If this change is approved, would it be possible to create a new release to use in the Pharo bootstrap please?
Thanks

Fixes #23

[jecisc]

There are two problems:

• First this version fails in Pharo 12 bootstrap while loading the TraitV2 package
• Second, now a test is failing in Pharo 12 but it was passing before so it might be related to a recent change in Pharo 12. The sad thing is that it is passing locally :( So it's hard to debug

[jecisc]

I found the origin of the test failure and it is from Pharo and not Hermes: pharo-project/pharo#15018

Now I'll check the second problem

[jecisc]

Both problems are now fix!