feat(cli): add extract integrity command

[clemgbld]

Closes #524

[PierreDemailly]

Could you add docs/cli/extract.md and update the README?

cli/README.md

Lines 100 to 113 in ab143c8

	For complete details on each command, refer to the following documents:
	- [`cwd`](./docs/cli/cwd.md)
	- [`from`](./docs/cli/from.md)
	- [`auto`](./docs/cli/auto.md)
	- [`open`](./docs/cli/open.md)
	- [`verify`](./docs/cli/verify.md)
	- [`summary`](./docs/cli/summary.md)
	- [`scorecard`](./docs/cli/scorecard.md)
	- [`report`](./docs/cli/report.md)
	- [`lang`](./docs/cli/lang.md)
	- [`config create`](./docs/cli/config.md)
	- [`config`](./docs/cli/config.md)
	- [`cache`](./docs/cli/cache.md)