Deprecate self custody feature

[gabririgo]

Summary

Remove the unused self-custody feature.

Motivation

The feature was added to provide further flexibility to professional market makers. As the feature never got used and breaks the condition that the pool is the owner of all owned tokens, it does not make sense to keep it. It also adds a point of attack where if the wallet of the pool operator is hacked and the conditions for using the feature are fulfilled, tokens can be transferred out of the pool.

Specification

Remove mapping of self-custody selectors to adapter contract. Remove the self-custody adapter in the authority smart contract.

Rationale

To maintain the integrity of the pool value estimation by the sum of the value of pool-owned tokens.

Notes

Feature code has been removed in this PR