support handlers being registered for (task definition) types

[nitram509]

motivation

currently, task handlers only can be registered for single Ids, which means just one element.
it would be a great extension, to allow a single task handler to be used for multiple types.
This would also increase compatibility with Zeebe.

acceptance criteria

• task handler can be defined for ID
• task handler can be defined for Type (as in extension taskDefinition)
• in case of overlapping task handler (id and type would match), the more specific one has precedence == ID first
• in case of overlapping task handler (id and/or type would match), only the first matching one is executed
• documentation describes details of how multiple task handlers are treated/executed

links

• was inspired by add TaskDefinition Info for global service task handler #57