refactor(core+parser) Move CTO parser/printer out of core into its own package

[jeromesimeon]

Signed-off-by: jeromesimeon [email protected]

Changes

This PR reorganizes the core Concerto code and API and splits it into three distinct packages:

1. @accordproject/concerto-util now contains utilities which are fundamentally generic and independent from Concerto itself. Currently those include:
   • TypedStack a general purpose stack data structure
   • Logger logging utility functions, with color support
   • Writer a file writer
   • *Loader classes for resolving URIs into their content with some built-in support for http and git URIs.
2. @accordproject/concerto-cto now contains support for CTO syntax including the parser, parse errors, and a pretty printer. The parser and pretty printer are base on instance of the concerto metamodel.
3. @accordproject/concerto-core the core support for building models (from instances of the metamodel) validating models, validating instances of the model, etc

Flags

• This is a breaking change
• The parser package still is a dependency for the core package (only used in the model manager)

Main breaking changes

1. The TypedStack class has been moved from @accordproject/concerto-core to @accordproject/concerto-util
2. The Writer class has been movedfrom @accordproject/concerto-core to @accordproject/concerto-util
3. The Logger class has been moved from @accordproject/concerto-core to @accordproject/concerto-util
4. The *ModelFileLoader classes have been moved from @accordproject/concerto-core to @accordproject/concerto-util and renamed to *FileLoader (no Model)
5. The parser and ParseException class have been moved from @accordproject/concerto-core to @accordproject/concerto-cto
6. The metamodel to CTO printer has been moved from @accordproject/concerto-core to @accordproject/concerto-cto
7. The ModelFile class now takes a metamodel instance (a concerto AST) as input rather than a cto string
8. The CLI commands concerto import and concerto export have been renamed to concerto parse and concerto print

[dselman]

Awesome - very clean! Just a couple of minor comments...