Add SerializationContext API for core payload/failure conversion paths

[THardy98]

What was changed

Added SerializationContext API for core payload/failure conversion paths (i.e. workflows and activities).

Scope of this PR is limited to core workflow/activity boundaries (as an effort to split: #1950 into easier to review chunks).

Specifically, the boundaries implemented in this PR are:

Boundary	Payload Context	Failure Context
Workflow start args	Workflow	N/A
Workflow result	Workflow	N/A
Workflow failure	N/A	Workflow
Query args/result	Workflow	N/A
Update args/result	Workflow	N/A
Signal receive payload	Workflow	N/A
Remote activity args/result	Activity	Activity
Remote activity failure observed by workflow	N/A	Activity
Remote activity heartbeat details	Activity	N/A
Local activity args/result	Activity (isLocal=true)	Activity (isLocal=true)
Local activity failure observed by workflow	N/A	Activity (isLocal=true)
Child workflow start args/result	Child workflow	Child workflow
Child workflow failure observed by parent	N/A	Child workflow
External workflow signal payload (success)	Target workflow	Target workflow
External workflow signal failure	N/A	Target workflow
External workflow cancel failure	N/A	Target workflow
Continue-as-new args	Workflow	N/A
Workflow memo upsert encode path	Workflow	N/A
Timer summary encode path	Workflow	N/A
Activity pre-start heartbeat-details decode failure	N/A	Activity

Note for reviewers:
The diff looks big but about half of it is the test suite at test-serialization-context.ts. It might be easier to review this PR starting there, to see what the serialization context across these boundaries look like.

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1. Part of [[Feature Request] Serialization context for codecs and converters #1661]

2. How was this tested:

• Comprehensive test suite at test-serialization-context.ts for the boundaries implemented
• Also a test in test-worker-heartbeating.ts to check serialization context is correct when activity start task fails (specifically when it fails during extractActivityInfo for a failed activity heartbeat, we want to check that the serialization context is propagated through the failure correctly).