Move py-cachetools to src folder am: c9b01f8f0f am: e0f6cd8182 am: 1036d9ce78 am: cfc2910233

Original change: https://android-review.googlesource.com/c/platform/external/python/cachetools/+/2219104

Change-Id: If92bb6fef8604faa21139823bbee7b35009a79a9
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>