Proto: Remove Token.`Double_signing_evidence_rewards

Context

Partly answers #4787.

Two functions indirectly leads to the use of the Double_signing_evidence_rewards infinite source: punish_double_baking and punish_double_endorsing.

Before the request, these functions would burn the punishing amount, return this value, and then mint the reward based on the value.

Now, the functions calculates the punishing amount, separate it into an amount to burn and a reward amount (such that punish = burn + reward), burns the amount to burn, and returns the reward that will be transferred in Apply.

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