[Task]: Update ReadFromBigTable and WriteToBigTable naming to lower "t"

[derrickaw]

What needs to happen?

Industry standards is to use lower "t" for "Table". At quick glance, it seems its appropriately used in in most places except in Yaml usage.

• Double check non-yaml usage of "Bigtable" and ensure not "BigTable"
• Correct usage in Yaml from "BigTable" to "Bigtable" for ReadFromBigTable and WriteToBigTable

Issue Priority

Priority: 2 (default / most normal work should be filed as P2)

Issue Components

• Component: Python SDK
• Component: Java SDK
• Component: Go SDK
• Component: Typescript SDK
• Component: IO connector
• Component: Beam YAML
• Component: Beam examples
• Component: Beam playground
• Component: Beam katas
• Component: Website
• Component: Infrastructure
• Component: Spark Runner
• Component: Flink Runner
• Component: Prism Runner
• Component: Twister2 Runner
• Component: Hazelcast Jet Runner
• Component: Google Cloud Dataflow Runner