This change adds an operations provider for GCP. Right now, it can
just collect logs from google cloud functions, similar to `gcloud
functions logs read`
Parallelize collection of logs at each layer of the resource tree walk. Since almost all cost of log collection is at leaf nodes, this should allow the total time for log collection to be close to the time taken for the single longest leaf node, instead of the sum of all leaf nodes.
We need to clear the resource filter during the resource tree walk to ensure that logs from children of matched resources are collected and aggregated.