Remove more obsolete v1 logic

[stephen-soltesz]

This change removes obsolete logic from the v1 data pipeline, including:

• cloud/bq/sanity.go
• LocalSaver logic
• the v1 client library (now replaced by the v2 client library).

Part of:

• https://github.com/m-lab/etl/issues/1084

---

This change is 

[coveralls]

Pull Request Test Coverage Report for Build 3545

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+3.1%) to 77.117%

---

Totals
Change from base Build 3541:	3.1%
Covered Lines:	1284
Relevant Lines:	1665

---

💛 - Coveralls