remove CompoundManifest #851

Job	Run time
setup	2s
wheel_building / Build source and wheel distribution	5m 32s
asdf-schemas / Load tox environments	3s
core / Load tox environments	5s
asdf-schemas / asdf (ubuntu-latest)	2m 5s
asdf-schemas / asdf-standard (ubuntu-latest)	1m 24s
asdf-schemas / asdf-transform-schemas (ubuntu-latest)	1m 23s
asdf-schemas / asdf-coordinates-schemas (ubuntu-latest)	2m 9s
core / py39-parallel-cov (ubuntu-latest)	2m 8s
core / py39-test-devdeps-parallel-cov (ubuntu-latest)	2m 44s
core / py39-astropylts-parallel-cov (ubuntu-latest)	2m 20s
core / py39-transformlts-parallel-cov (ubuntu-latest)	2m 14s
dev	0s
numpy	0s
oldest	0s
test	0s
	22m 9s

Provide feedback