Implement update and delete commands over the wire

[schapman1974]

Allow supported clients to update, replace, upsert, and delete documents.

Acceptance criteria:

• Support ordered update and delete command batches.
• Distinguish replacement documents from update operators.
• Support multi, upsert, limit, and applicable arrayFilters as roadmap features land.
• Return matched, modified, removed, and upserted metadata compatibly.
• Return indexed writeErrors without dropping the connection.
• Add partial-failure and duplicate-key contracts.