Create EventSource and EventSink handles #3034

Job	Run time
Build specification using nix	53s
Build & test (plutus-cbor)	1m 50s
Build haddock using nix	5m 35s
Benchmarks (hydra-node, tx-cost, --output-directory $(pwd)/../benchmarks)	5m 17s
Build & test (plutus-merkle-tree)	1m 53s
Benchmarks (hydra-node, micro, -o $(pwd)/../benchmarks/ledger-bench.html)	4m 22s
Build & test (hydra-plutus)	1m 47s
Benchmarks (hydra-cluster, bench-e2e, datasets datasets/3-nodes.cbor datasets/1-node.cbor --outpu...	8m 39s
Build & test (hydra-tui)	6m 17s
Benchmarks (plutus-merkle-tree, on-chain-cost, $(pwd)/../benchmarks)	2m 4s
Build & test (hydra-node)	7m 25s
Build & test (hydra-cluster)	11m 49s
Publish benchmark results	0s
Publish test results	1s
Documentation	1s
	57m 53s

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