Add mediator and simple client implementation #6281

Job	Run time
workflow-setup	27s
aries_vcx_clippy (credx,vdrtools_wallet)	3m 23s
workspace_clippy	5m 15s
aries_vcx_clippy (vdr_proxy_ledger)	4m 31s
verify-code-formatting	23s
aries_vcx_core_clippy (credx,vdrtools_wallet)	2m 48s
aries_vcx_core_clippy (vdr_proxy_ledger)	4m 34s
aries_vcx_no_features_clippy	2m 33s
test-unit-workspace	3m 9s
test-integration-aries-vcx	16m 37s
workflow-setup-check	1s
code-coverage-aries-vcx-integration-modular-libs	17m 40s
build-docker-vdrproxy	9s
test-integration-aries-vcx-mysql	3m 55s
test-integration-did-crate	2m 45s
test-integration-libvcx	2m 46s
test-integration-node-wrapper (18.x)	11m 22s
x86_64-unknown-linux-gnu	9m 31s
x86_64-unknown-linux-musl	9m 2s
x86_64-apple-darwin	8m 53s
aarch64-apple-darwin	25m 5s
test-integration-aries-vcx-vdrproxy	13m 44s
publish-docker-vdrproxy	12s
make-release	0s
publish-napi	1m 8s
publish-node-wrapper	28s
publish-agent-core	53s
	2h 31m 14s

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