Change dcp-diag tools to use HCA auth0 rather than danielvaughan auth0

[justincc]

As per @sampierson, dcp-diag uses the same kind of IngestAuthAgent code that the integration tests do.

The ingest code to allow HCA auth0 use is in integration. The danielvaughan account has an extension till the end of January but it's best to assume it could go away at any point.

[justincc]

See HumanCellAtlas/ingest-core#197

[aaclan-ebi]

Noting here the changes to Ingest Auth Agent in integration test: https://github.com/HumanCellAtlas/dcp/compare/f9faea2..472bf86