Options for submodule recurse.

Represent the value of submodule.$name.fetchRecurseSubmodules

• GIT_SUBMODULE_RECURSE_NO - do no recurse into submodules
• GIT_SUBMODULE_RECURSE_YES - recurse into submodules
• GIT_SUBMODULE_RECURSE_ONDEMAND - recurse into submodules only when commit not already in local clone