Dac: move protocol-dependent logic to own plugin

Context

The management of Dac will become considerably more complex in the next months. Therefore, it is better to isolate the protocol-related logic of Dac from Dal. This amounts to moving the DAC RPC server and related files, currently part of the Dal plugin, to a new Dac plugin.

To ensure that DAC can be released before protocol N, support for Mumbai is added for the protocol plugin

Closes: #4544 (closed)

Manually testing the MR

Relying on the CI passing

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR