Add support for event streaming API

[jribbink]

This PR introduces the event streaming API & some infrastructure needed to enable streaming other realtime execution data.

• New SDK response type introduced for "stream connection". These are represented by a lightweight interface defined in @onflow/types. Currently these streams are built using event emitters, however, this implementation can easily be substituted with our own in the future if necessitated
• Resolving data streams in the SDK is defined as piping their contents to a new stream which separates data types by domain & resolves contents. (i.e. as of now we have both "events" and "heartbeat" data types passing through the event stream)
• Websocket connections are built to reconnect to streams in the event of a disconnection/error. The event stream connection will always reconnect with the next blockId selected to resume its position

Currently, events streaming is only available on testnet. This PR cannot be merged until this feature exists on mainnet (or needs an experimental feature config flag). Release is also blocked by a couple of outstanding issues with REST events streaming.

• [Access] WebSockets event streaming returns CCF encoded events flow-go#5047 (awaiting AN deployment)
• [Access] Event streaming is missing block timestamp in responses flow-go#4911 (soft block, streaming events will still work without, however, timestamps will be undefined even though they are typed as string in the code)

[changeset-bot]

🦋 Changeset detected

Latest commit: 6b5b423

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 6 packages

Name	Type
@onflow/transport-grpc	Patch
@onflow/fcl	Minor
@onflow/sdk	Minor
@onflow/transport-http	Minor
@onflow/typedefs	Minor
@onflow/fcl-wc	Major

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[nialexsan]

looks good