Root hierarchy + identifiers (v3)

[jeromesimeon]

Description

This PR addresses feedback and some critical issues in Concerto 1.0.0-alpha.2

Changes

Major

Several critical fixes to Concerto 1.0.0-alpha.2:

• Do not automatically generate identifiers when they are meant to be user-provided (Concerto 1.0 generates identifiers even when they should be user-provided #244)
• Adds back root types for Participant Asset Transaction and Event (Root types have disappeared #228)
• System types in the concerto.* namespace are now automatically imported
• Fixes inconsistent identifiers handling when used in conjunction with the type hierarchy (fix(core) Root hierarchy should have proper inheritance (v2) #240)
• timestamp is now $timestamp and only system-generated (Which classes should have timestamps? #242)
• Fixed functional API validation for classes with a system identifier (The new validation API does not like system generated identifiers #249)

Tests

• Fixes wrong tests
• Adds tests for both classic and "functional" validation

Misc

• Remove some unused code, notably old system model

API

• model classes (Resource, Identifiable, etc) now take an (optional) timestamp parameter
• ClassDeclaration methods for identifiers are now semantic (is the class is identifiable) rather than syntactic (does the class declaration have an identified or identified by)

CLI

• Adds --functional option to try the new validation API (CLI support for functional API #243)
• Align with markus CLI: --ctoFiles --> --model and --sample --> --input

[jeromesimeon]

@dselman Lots more should be done, notably with testing, but this is in decent shape now and a lot of changes. I'm going to consider this PR ready for review.

[dselman]

LKTM