15716: Don't include modules on .rake files

15716: Don't include modules on .rake files

The file symbols.rake used to include CurrentApiClient, making its methods
available to the entire app as Object class methods.
This made several tests to pass successfully while the code they exercised
really fail on production and development environments.

The solution is to make a helper class that works as a namespace of those
methods.

This commit exposes 41 failing tests.

Arvados-DCO-1.1-Signed-off-by: Lucas Di Pentima <ldipentima@veritasgenetics.com>