[WIP] Improved Trapezoidal Mapping for FGM

[tkiymaz]

Proposed Changes

The original trapezoidal map implementation needs excessive memory for large lookup tables (LUT) (e.g., 300+ MB for tables with ~80k points). This PR introduces a new memory-efficient trapezoidal map implementation (LUT_FAST) for Flamelet-Generated Manifold (FGM) lookup tables, based on LUT algorithm of Pedro Gomes. The new implementation reduces memory usage while maintaining query performance. A new unit test is created and all tests are passed.

Related Work

This code is an implementation of https://github.com/pcarruscag/LUT to SU2.

PR Checklist

• I am submitting my contribution to the develop branch.
• My contribution generates no new compiler warnings (try with --warnlevel=3 when using meson).
• My contribution is commented and consistent with SU2 style (https://su2code.github.io/docs_v7/Style-Guide/).
• I used the pre-commit hook to prevent dirty commits and used pre-commit run --all to format old commits.
• I have added a test case that demonstrates my contribution, if necessary.
• I have updated appropriate documentation (Tutorials, Docs Page, config_template.cpp), if necessary.

[bigfooted]

Let's first change
LUT -> LUT_OLD
LUT_FAST -> LUT

and see how much the residuals deviate here on github. if it is not too much, then remove the old implementation.