<!--Delete sections as needed -->
https://docs.docker.com/engine/security/rootless/ was too lengthy and
giving a false sense that Rootless mode was quite clunky and hard to
use, although actually it can be just set up in a single command:
```
dockerd-rootless-setuptool.sh install
```
## Description
<!-- Tell us what you did and why -->
### Commit 1: `engine/security/rootless: split to multiple pages`
This commit only splits the page.
The content will be updated in subsequent commits.
### Commit 2: `engine/security/rootless: remove outdated/duplicated
info`
Setup:
- `dockerd-rootless-setuptool.sh` has been improved to show help when
the prerequisites are not satisfied.
Users no longer need to read the **lengthy** "prerequisites"
documentation unless they encounter issues.
- The document had duplicated descriptions about dbus, uidmap, and
machinectl stuffs in several places.
Graph drivers:
- Rootless OverlayFS has been merged into the upstream since kernel
5.11:
torvalds/linux@459c7c565a .
Ubuntu no longer patches the kernel.
- FUSE-OverlayFS is typically no longer needed on the current supported
distros,
except EL 8.
SELinux:
- Remove a workaround for an issue that was already fixed in Docker
Engine v20.10.8.
CLI:
- `docker context use rootless` no longer needs to be executed manually,
since Docker v23. (moby/moby#43061)
## Related issues or tickets
<!-- Related issues, pull requests, or Jira tickets -->
## Reviews
<!-- Notes for reviewers here -->
<!-- List applicable reviews (optionally @tag reviewers) -->
- [X] Technical review
- [X] Editorial review
- [ ] Product review
## Preview
https://deploy-preview-23302--docsdocker.netlify.app/engine/security/rootless/
---------
Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
Co-authored-by: Paweł Gronowski <me@woland.xyz>
Co-authored-by: Allie Sadler <102604716+aevesdocker@users.noreply.github.com>
