Move py-jinja to src folder am: fec0515194 am: 6e27281228

Original change: https://android-review.googlesource.com/c/platform/external/python/jinja/+/2215007

Change-Id: Ia4d906d2d9956f4d05160fa08eab30725c92dcab
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>