Add mediator and simple client implementation #6239

Job	Run time
workspace_clippy	5m 51s
verify-code-formatting	22s
aries_vcx_clippy (credx,vdrtools_wallet)	3m 45s
aries_vcx_clippy (vdr_proxy_ledger)	4m 42s
workflow-setup	34s
aries_vcx_core_clippy (credx,vdrtools_wallet)	2m 53s
aries_vcx_core_clippy (vdr_proxy_ledger)	4m 32s
aries_vcx_no_features_clippy	2m 31s
test-unit-workspace	2m 52s
build-docker-vdrproxy	12s
workflow-setup-check	1s
code-coverage-aries-vcx-integration-modular-libs	16m 8s
test-integration-aries-vcx	16m 17s
test-integration-aries-vcx-mysql	3m 47s
test-integration-did-crate	3m 57s
test-integration-libvcx	3m 43s
test-integration-node-wrapper (18.x)	10m 33s
x86_64-unknown-linux-gnu	10m 15s
x86_64-unknown-linux-musl	10m 12s
x86_64-apple-darwin	16m 6s
aarch64-apple-darwin	48m 46s
test-integration-aries-vcx-vdrproxy	16m 47s
publish-docker-vdrproxy	15s
make-release	0s
publish-napi	3m 56s
publish-node-wrapper	0s
publish-agent-core	0s
	3h 8m 57s

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