SecretStore: service pack 1 (#8435)

* SecretStore: error unify initial commit

SecretStore: pass real error in error messages

SecretStore: is_internal_error -> Error::is_non_fatal

warnings

SecretStore: ConsensusTemporaryUnreachable

fix after merge

removed comments

removed comments

SecretStore: updated HTTP error responses

SecretStore: more ConsensusTemporaryUnreachable tests

fix after rebase

* SecretStore: unified SS contract config options && read

* SecretStore: service pack

SecretStore: service pack (continue)

* fixed grumbles