Remove "apiclient" package

[kruton]

apiclient package was created in 2014 as a stop-gap to help people transition from "apiclient" to googleapiclient. This transition should have been completed in the past 10 years.

However now this is creating package pollution that interferes with another PyPI package called api-client that also writes to …/site-packages/apiclient/ and conflicts with this package.

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Fixes #2485 🦕

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[kruton]

Rebased onto newest commit.

[kruton]

Rebased onto head