feat(http): support custom auth types (#9053)

docs/usage/configuration-options.md

lib/config/definitions.ts

lib/datasource/npm/__snapshots__/get.spec.ts.snap

lib/datasource/npm/get.spec.ts

lib/types/host-rules.ts

lib/util/http/auth.spec.ts

lib/util/http/auth.ts

lib/util/http/host-rules.spec.ts

lib/util/http/host-rules.ts

lib/util/http/types.ts