Added Surface Python interface

[ahcorde]

Signed-off-by: ahcorde ahcorde@gmail.com

🎉 New feature

This PR is part of this meta ticket #931

Summary

Added Surface Python interface

Test it

from sdformat import Surface, Contact

surface = Surface()
contact = Contact()

Checklist

• Signed all commits for DCO
• Added tests
• Added example and/or tutorial
• Updated documentation (as needed)
• Updated migration guide (as needed)
• codecheck passed (See contributing)
• 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-commenter]

Codecov Report

Merging #940 (9bbc9e5) into main (66c1609) will decrease coverage by 0.04%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##             main     #940      +/-   ##
==========================================
- Coverage   87.99%   87.94%   -0.05%     
==========================================
  Files         106      107       +1     
  Lines       14826    14859      +33     
==========================================
+ Hits        13046    13068      +22     
- Misses       1780     1791      +11     

Impacted Files	Coverage Δ
python/src/sdf/pySurface.cc	64.51% <64.51%> (ø)
python/src/sdf/_ignition_sdformat_pybind11.cc	100.00% <100.00%> (ø)

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