Extend ogre 1.x custom shaders support

[iche033]

🎉 New feature

Related gazebosim/gz-sim#2002 (comment)

Summary

Extended to support features needed to render waves:

• 2d textures
• cubemap textures
• constant variables

Code is ported from the ogre2 implementation

Test it

Build and run the waves example

# ogre 1.x is used when no args are supplied
./waves

Sky is not supported yet in ogre 1.x so you'll only see waves in this demo:

Checklist

• 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)
• 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]

Codecov Report

Merging #908 (2270af2) into gz-rendering7 (5892355) will increase coverage by 0.40%.
The diff coverage is n/a.

❗ Current head 2270af2 differs from pull request most recent head d82b0f2. Consider uploading reports for the commit d82b0f2 to get more accurate results

@@                Coverage Diff                @@
##           gz-rendering7     #908      +/-   ##
=================================================
+ Coverage          77.23%   77.63%   +0.40%     
=================================================
  Files                170      170              
  Lines              14724    14724              
=================================================
+ Hits               11372    11431      +59     
+ Misses              3352     3293      -59     

Files	Coverage Δ
ogre2/src/Ogre2Material.cc	85.10% <ø> (+8.45%)	⬆️

[ahcorde]

Minor style issues. is it possible to add a test ?

[iche033]

is it possible to add a test ?

yep, will add one

[iche033]

yep, will add one

Added INTEGRATION_waves test that verifies waves can be rendered. Shaders and materials files for the test are taken from the waves demo. 20ca0c7

[ahcorde]

Just a minor comment