doc/cephadm: remove sections not apply to Squid in rgw.rst

doc/cephadm: remove sections not apply to Squid in rgw.rst

4949311 backported changes that do not apply to Squid.
PR #63073 body and the commit referenced therein as cherry-pick do not
correspond to the diff. Remove the additions that do not apply to Squid:

- Wildcard SAN feature in 3c24753 only since Tentacle.
- Shutdown delay feature in b84bb72 only since Tentacle.

The third feature doc addition is valid, d620ba6 was backported to Squid
in PR #61350 for disable multisite sync traffic, commit 59b3f28. This
backport cherry-picked only the feature addition and missed the docs
commit 8878619. Leave this section in.

Signed-off-by: Ville Ojamo <14869000+bluikko@users.noreply.github.com>