allow installing requirements without dataclasses

[iddo-yadlin]

Describe the bug
interrupts with installation of package on python3.8 and above.

To Reproduce
run pip install -r requirements.txt on python3.8 and above

Expected behavior
installation is completed successfully

Screenshots
If applicable, add screenshots to help explain your problem.

Environment:

• OS: mac
• Python version: python 3.10
• TDC version: 1.1.5
• Any other relevant information:

Additional context
dataclasses is an internal package for python 3.8 and above. you can't install dataclasses for python versions above that. I suggest to either remove dataclasses and drop support for older python versions, or allow installing without dataclasses with an extras marker. with the extras marker, I will be able to install with 'pip install pytdc[new]'