DAL: Remove statuses storage

What

Remove status_store information for DAL node.

Why

This information can be retrieve from info from the skip list.

How

Remove the on-disk data, and re-implement get_slot_status with:

1. A cache for recent data
2. Info retrieved from the skip list if not available in the cache

⚠️ ⚠️ ⚠️

As the new implementation rely on the skip_list, you have to use a producer DAL node in order to get info. This is a breaking change compared to the current behavior. Note that recent data is in cache even for observer nodes, which might or might not be something we want

⚠️ ⚠️ ⚠️

Manually testing the MR

I only thing that I tested was to have two dal nodes running, manually checking info reported by the /levels/.../slots/.../status RPC.

• Some empty answer (not found) from previous implementation now might return an error instead of empty response. e.g.

  [{"kind":"permanent","id":"dal.node.no_plugin_for_given_level","level":10}]

  I am not sure about what to do with this.

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