[docs]add cache information in raw containers doc

[popojk]

Tracking issue

Closes #4461

Why are the changes needed?

In document user_guide/customizing_dependencies/raw_containers.html lacks information about cache configuration in Flyte's ContainerTask.

What changes were proposed in this pull request?

1. Add information about cache configuration in Flyte's doc user_guide/customizing_dependencies/raw_containers.html.
2. Add example code in flytesnacks, please refer to this PR.

Check all the applicable boxes

• I updated the documentation accordingly.
• All commits are signed-off.

Related PRs

flytesnacks PR

Docs link

Raw containers

[welcome]

Thank you for opening this pull request! 🙌

These tips will help get your PR across the finish line:

• Most of the repos have a PR template; if not, fill it out to the best of your knowledge.
• Sign off your commits (Reference: DCO Guide).

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 36.71%. Comparing base (bdaf79f) to head (452f84e).
Report is 10 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #5876   +/-   ##
=======================================
  Coverage   36.71%   36.71%           
=======================================
  Files        1304     1304           
  Lines      130081   130081           
=======================================
  Hits        47764    47764           
  Misses      78147    78147           
  Partials     4170     4170           

Flag	Coverage Δ
unittests-datacatalog	51.58% <ø> (ø)
unittests-flyteadmin	54.41% <ø> (ø)
unittests-flytecopilot	11.73% <ø> (ø)
unittests-flytectl	62.40% <ø> (ø)
unittests-flyteidl	6.89% <ø> (ø)
unittests-flyteplugins	53.62% <ø> (ø)
unittests-flytepropeller	42.84% <ø> (ø)
unittests-flytestdlib	54.78% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[Future-Outlier]

docs link should be this:
https://flyte--5876.org.readthedocs.build/en/5876/user_guide/customizing_dependencies/raw_containers.html

[welcome]

Congrats on merging your first pull request! 🎉