Add support for state.gate

1. Add support for state.gate such as state.h
2. Add more examples

What's Changed

• RZ gate by @jessding in #1
• [major] merge pruning branch to master by @Hanrui-Wang in #2
• Jiaqi by @JeremieMelo in #3
• Jiaqi by @JeremieMelo in #4
• Params shift by @abclzr in #6
• Corrected module name to import MNIST by @googlercolin in #23
• modify doc conf to init docstring publish task by @frogcjn in #24
• refine class template by @frogcjn in #25
• [minor] update format and theme by @frogcjn in #26
• [minor] adjust dark theme code block and add function template by @frogcjn in #27
• add customized furo doc theme by @frogcjn in #28
• [doc] add ipynb and md support into doc, add one example by @frogcjn in #29
• [major] fix bugs in torchquantum/measure.py by @abclzr in #30
• [doc] Fix examples page in examples/index.rst by @frogcjn in #31

New Contributors

• @jessding made their first contribution in #1
• @Hanrui-Wang made their first contribution in #2
• @JeremieMelo made their first contribution in #3
• @abclzr made their first contribution in #6
• @googlercolin made their first contribution in #23
• @frogcjn made their first contribution in #24

Full Changelog: https://github.com/mit-han-lab/torchquantum/commits/v0.1.2