feat: add environment tags

This PR adds `rl-environment` and `verifiers` tags for RL Environments discovery. Compatibility for the code subset is defined in the [official environment integration](https://github.com/PrimeIntellect-ai/research-environments/blob/main/environments/code/i3_code/i3_code/taskset.py).

README.md

@@ -1,4 +1,7 @@
 ---
+tags:
+- rl-environment
+- verifiers
 dataset_info:
 - config_name: code
   features: