v2.0.0

This is a clean up release that fixes some gaps in the API:

• Remove SLF4JMethod.Loose -- this API exactly replicated SLF4J.
• Extend SLF4JMethod to use many parameters, just like case classes do: no more need for Arguments unless more than 20ish.
• Move the DSL/AST out to its own package and make blindsight-logstash depend on DSL. This keeps sourcecode impl working but does not require DSL in core. Should not be user visible.
• Extend Arguments
• Added more documentation on when to use Blindsight vs Echopraxia: optional structured logging vs required structured logging.