Iox #482 rework overview

[FerdinandSpitzschnueffler]

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. Branch follows the naming format (iox-#123-this-is-a-branch)
4. 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)
5. Update the PR title
   • Follow the same conventions as for commit messages
   • Link to the relevant issue
6. Relevant issues are linked
7. Add sensible notes for the reviewer
8. All checks have passed (except task-list-completed)
9. Assign PR to reviewer

Notes for Reviewer

In this PR I reworked the overview.md and fixed some links.

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

• Partially closes Extend documentation for 1.0 release and website #482

[codecov]

Codecov Report

Merging #699 (a6aee3c) into master (a62858e) will decrease coverage by 0.03%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #699      +/-   ##
==========================================
- Coverage   74.53%   74.50%   -0.04%     
==========================================
  Files         315      315              
  Lines       11213    11213              
  Branches     1969     1969              
==========================================
- Hits         8358     8354       -4     
- Misses       2081     2083       +2     
- Partials      774      776       +2     

Flag	Coverage Δ
unittests	74.45% <ø> (-0.04%)	⬇️
unittests_timing	31.13% <ø> (-0.21%)	⬇️

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

Impacted Files	Coverage Δ
iceoryx_utils/source/posix_wrapper/timer.cpp	60.52% <0.00%> (-0.88%)	⬇️
...nternal/roudi/introspection/port_introspection.inl	71.89% <0.00%> (-0.73%)	⬇️
...ils/include/iceoryx_utils/internal/cxx/smart_c.inl	89.06% <0.00%> (ø)