Shorten names of executables

[azeey]

🎉 New feature

Summary

Shortens executable names from sdformat2mjcf -> sdf2mjcf and mjcf2sdformat ->mjcf2sdf. Also updates documentation regarding installing sdformat from nightlies instead of building from source.

Test it

Run sdf2mjcf or mjcf2sdf.

Checklist

• [x] Signed all commits for DCO
• [ ] Added tests
• [ ] Added example and/or tutorial
• [ ] Updated documentation (as needed)
• [ ] Updated migration guide (as needed)
• [ ] Consider updating Python bindings (if the library has them)
• [x] codecheck passed (See contributing)
• [x] All tests passed (See test coverage)
• [ ] While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.

[codecov[bot]]

Codecov Report

Merging #99 (d0a777e) into main (9ae088d) will not change coverage. The diff coverage is n/a.

:exclamation: Current head d0a777e differs from pull request most recent head 9b21b20. Consider uploading reports for the commit 9b21b20 to get more accurate results

@@           Coverage Diff           @@
##             main      #99   +/-   ##
=======================================
  Coverage   95.15%   95.15%           
=======================================
  Files          24       24           
  Lines        1177     1177           
=======================================
  Hits         1120     1120           
  Misses         57       57           

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update 06d9b30...9b21b20. Read the comment docs.