docs(tvix): move most of //tvix/eval README up to //tvix r/5725

While moving the CLI out of the evaluator, we forgot to update the
README in //tvix/eval. Move this up to //tvix, so people know where
to start.

Keep the instructions on how to build only `//tvix/eval` in `//tvix/
eval/README.md`.

Change-Id: Ie2755e8b5a0056225dbf3a0ee040f70f7f6a1f27
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7887
Reviewed-by: sterni <sternenseemann@systemli.org>
Autosubmit: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>

0 files changed, 0 insertions, 0 deletions