Merge branch 'examples' into 'main'

docs/source/documentation/algorithm.md

docs/source/documentation/mf_notes.md

docs/source/index.md

docs/source/tutorial/graphene_example.md

docs/source/tutorial/hubbard_1d.md

examples/1d_hubbard_totalenergy.ipynb

examples/codes

examples/diatomic_molecule.ipynb

examples/graphene_extended_hubbard.ipynb

examples/mexican_hat.ipynb