This adds an initial implementation of the so-called "German Strings" in Rust.
https://cedardb.com/blog/german_strings/
This implementation is *far from* complete, the only thing that can be done
right now is construct a string, and even that I'm not fully happy with.
Change-Id: I2697932a0ef373be76ffd14d59677493a5783b58
Reviewed-on: https://cl.tvl.fyi/c/depot/+/12234
Autosubmit: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
