feat: add mutator to modify discovered endpoints

[vitalyisaev2]

Feature Request

Describe the Feature Request

We'd like to use underlay networks when accessing Dedicated Managed YDB. To achieve this, we need to transform the output of ListEndpoints.

Describe Preferred Solution

Something similar to mutator from C++ SDK.

Describe Alternatives

Make custom rules in puncher every time when a new client comes.

Related Code

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Additional Context

For details please see YQ-3163 in/

If the feature request is approved, would you be willing to submit a PR? Yes