Add Switch task implementation

[fjtirado]

Implements https://github.com/serverlessworkflow/specification/blob/main/dsl-reference.md#switch

[mcruzdev]

Hi @fjtirado could you assign it o me?

[fjtirado]

@mcruzdev Im already working on it. Its a pretty complex one affecting the whole structure of the implementation.
Maybe, if you are willing to contribute to the spec, you can work on serverlessworkflow/specification#1030, wdyt?

In fact, the reason I have not uploaded the PR yet is that there is an ongoing discussion on CNCF about the possible values of task names on then: which heavily impacts the implementation.

[fjtirado]

@mcruzdev Knowing that you want to work on the reference implementation, once I have completed this one and error handlng (both affects the current TaskExecutor interface) I would open more issues and discuss which ones can you help me with. Im thinking on authorization support for http calls and openapi task, but, in order to avoid collisions, I have to finish this one first.