Tarantool Kubernetes Operator documentation

Part of Tarantool documentation, published to https://www.tarantool.io/en/doc/latest/book/cartridge/cartridge_kubernetes_guide/

Create pot files from rst

python -m sphinx doc doc/locale/en -c doc -b gettext

Create/update po from pot files

sphinx-intl update -p doc/locale/en -d doc/locale -l ru

Build documentation to doc/output

python -m sphinx doc doc/output -c doc