iox-#924 Add icedocker example readme

[elfenpiff]

Pre-Review Checklist for the PR Author

1. Code follows the coding style of CONTRIBUTING.md
2. Tests follow the best practice for testing
3. Changelog updated in the unreleased section including API breaking changes
4. Branch follows the naming format (iox-#123-this-is-a-branch)
5. Commits messages are according to this guideline
   • Commit messages have the issue ID (iox-#123 commit text)
   • Commit messages are signed (git commit -s)
   • Commit author matches Eclipse Contributor Agreement (and ECA is signed)
6. Update the PR title
   • Follow the same conventions as for commit messages
   • Link to the relevant issue
7. Relevant issues are linked
8. Add sensible notes for the reviewer
9. All checks have passed (except task-list-completed)
10. Assign PR to reviewer

Notes for Reviewer

Checklist for the PR Reviewer

• Commits are properly organized and messages are according to the guideline
• Code according to our coding style and naming conventions
• Unit tests have been written for new behavior
• Public API changes are documented via doxygen
• Copyright owner are updated in the changed files
• PR title describes the changes

Post-review Checklist for the PR Author

1. All open points are addressed and tracked via issues

References

• Closes Write example on how to use iceoryx in a docker environment #924
• Closes commmunicate between two nodes from different docker containers #899

[elfenpiff]

@r7vme Ping, could you please have a look at this PR?

[codecov]

Codecov Report

Merging #925 (2b0aeaf) into master (8e2edeb) will increase coverage by 1.80%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #925      +/-   ##
==========================================
+ Coverage   75.71%   77.52%   +1.80%     
==========================================
  Files         335      335              
  Lines       12222    12267      +45     
  Branches     2038     1831     -207     
==========================================
+ Hits         9254     9510     +256     
+ Misses       2178     2131      -47     
+ Partials      790      626     -164     

Flag	Coverage Δ
unittests	76.42% <ø> (+1.78%)	⬆️
unittests_timing	30.35% <ø> (+0.77%)	⬆️

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

Impacted Files	Coverage Δ
iceoryx_hoofs/source/cxx/helplets.cpp	63.63% <0.00%> (-6.37%)	⬇️
iceoryx_posh/source/roudi/service_registry.cpp	96.92% <0.00%> (-3.08%)	⬇️
...e/relocatable_pointer/base_relocatable_pointer.cpp	12.50% <0.00%> (-2.66%)	⬇️
iceoryx_hoofs/source/log/logging.cpp	100.00% <0.00%> (ø)
iceoryx_hoofs/source/log/logmanager.cpp	63.33% <0.00%> (ø)
iceoryx_hoofs/platform/linux/source/grp.cpp	100.00% <0.00%> (ø)
iceoryx_hoofs/platform/linux/source/file.cpp	100.00% <0.00%> (ø)
iceoryx_hoofs/platform/linux/source/mman.cpp	100.00% <0.00%> (ø)
iceoryx_posh/source/gateway/gateway_base.cpp	0.00% <0.00%> (ø)
iceoryx_hoofs/platform/linux/source/fnctl.cpp	100.00% <0.00%> (ø)
... and 58 more

[r7vme]

LGTM