FEAT: add unevaluated integral class #383

Job	Run time
style / Determine skipped pre-commit hooks	10s
pytest / Determine job matrix	7s
doc / nb / Execute and build documentation	1m 16s
doc / linkcheck / Check external links	1m 10s
pytest / Run unit tests (3.10, ubuntu-22.04)	59s
pytest / Run unit tests (3.11, ubuntu-22.04)	58s
pytest / Run unit tests (3.12, ubuntu-22.04)	1m 8s
pytest / Run unit tests (3.7, ubuntu-22.04)	1m 14s
pytest / Run unit tests (3.8, ubuntu-22.04)	1m 9s
pytest / Run unit tests (3.9, ubuntu-22.04, ampform)	2m 4s
pytest / Run unit tests (3.9, macos-12)	1m 44s
style / Run taplo through pre-commit	22s
style / Run local pre-commit hooks	1m 45s
doc / Upload to GitHub Pages	0s
style / Push changes	0s
	14m 6s

Provide feedback