3.12.0: Start of DAL implementation, independent of the database

Add dal2.HttpStubDAO and impl for MongoDB that hides logic of building
queries to Database.

Added a DSL that lets describe an action sequence and then  generates
scalatest, executing it and markdown files containing curl commands
for these actions.

Mockingbird 3.11.0

• ReInit triggers for sources (#69 & #80)
• Explicitly define bson instances for GrpcMessageSchema (#85)
• Fix building mockingbird under Mac with Apple Silicone CPU (#82)

Mockingbird 3.10.0

• trim strings on front (#72)
• add $[_] keyword in predicate DSL (#76)

Mockingbird 3.9.2

• Enable initialization of tracing context (#71)

Mockingbird 3.9.1

• Properly render JsonResponse in schema (#68)

Mockingbird 3.9.0

• Support header values for state search (#62)

Mockingbird 3.8.0

• brand-new UI by @Metastasis

Mockingbird 3.7.2

• Support body for any http verb (#52)

Mockingbird 3.7.1

• Improve behavior of JsonOptic.set (#49)

Mockingbird 3.7.0

• Configurable healthcheck endpoint (#45)
• Smart templating (#44)