Implement diffraction module

See merge request !15

Feat: Add UTD Diffraction module (with tests for compute method and utility methods)

See merge request !21

GLM does not export its symbols, so it cannot be built as a shared
library on windows without changes like this:
https://github.com/g-truc/glm/pull/1280/files

This reverts commit 307da2ea.

Adapt CreateWedge method: now takes the propagation_path_list anchor as paramater and extracts the necessary information itself. Also add parameter documentation

Feature: Test the propagation parameter creation of the PPE

See merge request !22

Feat: implement spreading loss for PPE

See merge request !13

# Conflicts:
#   CMakeLists.txt

Feat: add and test export to impulse responses from PPE/pelican

See merge request !19

# Conflicts:
#   CMakeLists.txt

Feat: add air attenuation ISO9613

See merge request !18

Feat: add frequency axis to config data structure

See merge request !16

# Conflicts:
#   CMakeLists.txt

Test: change in speed of sound influences prop delay

See merge request !20

Co-authored-by: Chalotorn Möhlmann <chalotorn.moehlmann@akustik.rwth-aachen.de>

Co-authored-by: Chalotorn Möhlmann <chalotorn.moehlmann@akustik.rwth-aachen.de>

Remove local variable pi_rad in favor of M_PI constant and add more comments and docs for clarification and sources