Add a `.bazelrc` to configure the `--output_base`
Add a `.bazelrc` to configure the `--output_base`

This change adds a default `--output_base` to the bazel builder to make it store its outputs under `/workspace`.  This is because what lives under `/workspace/bazel-bin/` is actually just a set of symlinks to the actual outputs, so downstream build steps get to see the symlinks, but not the things to which those symlinks refer.

By moving the output based under `/workspace`, the symlinks will correctly resolve.
GoogleCloudPlatform/cloud-builders,google-octo/cloud-builders,GoogleCloudPlatform/cloud-builders,google-octo/cloud-builders,google-octo/cloud-builders,google-octo/cloud-builders,GoogleCloudPlatform/cloud-builders,GoogleCloudPlatform/cloud-builders,google-octo/cloud-builders,google-octo/cloud-builders,google-octo/cloud-builders,GoogleCloudPlatform/cloud-builders,GoogleCloudPlatform/cloud-builders,GoogleCloudPlatform/cloud-builders