Adds a number of user-accessable options for configuring internal git resource
cloning behavior.
- Git commands are executed with a configurable timeout by including a parameter
like "?timeout=2m30s" in the resource URL. This can improve cloning a large
repository, or over a slow network.
- Git submodule cloning can be disabled by including a parameter like
"?submodules=false" in the resource URL.
- Switch the overall query parsing to use url.Parse() and be more extensible.
