Remove TE v1 executor

[riccardofelluga]

What does this PR do?

After the latest update to transformer_engine library(2.10) this executor has stopped working and, since the TEv2 is now bringing the same functionality and more, it is time to move on :D

[crcrpar]

would there be some script and/or test to make sure there isn't unexpected regressions?

[riccardofelluga]

For convergence, we do compare outputs between Thunder TE executor and vanilla TE in the tests already, but regarding performance there aren't any specific tests but the benchmarks. If we were to compare performance we can do so by using benchmark_litgpt.py in something like this:

# Using TE executor
python thunder/benchmarks/benchmark_litgpt.py --model_name Llama-2-7b-hf --compile thunder --checkpoint_activations False --low_precision_mode fp8-default-te --use_sdpa False
# Using TE without Thunder
python thunder/benchmarks/benchmark_litgpt.py  --model_name Llama-2-7b-hf --compile eager --checkpoint_activations False --low_precision_mode fp8-default-te --use_sdpa False