Add doxygen infrastructure

[malleoz]

Doxygen will be an incredible resource to have as we expand Kinoko, in terms of test cases, coverage, and collaboration. In this PR, I've left comments for most functions that I felt comfortable describing, with the hope that the rest can be filled in over time.

The following is all features I've implemented that I can think of:

• @rename alias: Leaves a note in the documentation that the function has a poor name and should be renamed in the future
• @unused alias: Adds [unused] in the documentation
• @todo alias: Duh
• The above three aliases generate unique pages when navigating to "TODO" in the nav bar.
• @addr alias: Displays a function's address as a "qualifier" to the right of the function signature
• @stage alias: Adds bolded text in the documentation to specify what stage of the race the function (can) run during. This may not be fully present in parts of the documentation I've added...
• LaTeX examples - KColData::GetVertex and EGG::Quatf::dot
• Separate Setter/Getter functions from other members in the list
  • Standardized that setters come before getters (hope this is okay)

Future improvements:

• General HTML/CSS adjustments
• Add Discord link to header nav bar
• Main page besides README.md
• Better navigation hierarchy

I'd like to establish the following precedents:

• New functions must, at a minimum, have a brief description, as well as a @addr{0x80XXXXXX} command that maps that function to its in-game counterpart (if applicable).
• Any new member variables must have a brief description in the header file.
• Getter and setter functions, specifically ones which do not have an in-game counterpart and are used solely to accomodate C++ access specifiers, must be wrapped within a @beginSetters...@endSetters and @beginGetters...@endGetters.
• Any new classes must have a brief description.

[vabold]

host/System.cc also has ties to the base game, as KSystem is modeled loosely on RKSystem. The corresponding addresses are as follows:

KSystem::main - 80008ef0
KSystem::init - 80009194
KSystem::run - 8000951c

[malleoz]

Accounted for all of @vabold's comments above. Also applied the following changes (some may be duplicates of vabold's comments)

• Add missing addr to EGG::Scene::~Scene
• Move EGG::Decomp::DecodeSZS @brief to source file
• Move EGG::Scene setter/getter bodies to source file. Group setters/getters documentation
• Rename EGG::Matrix34f::inverseTo to inverseTo33
• Add missing addr to EGG::Sphere3f::isInsideOtherSphere
• Add missing addr to EGG::Vector3f::normalise as well as specifying the optional return value
• Remove TODO comment above EGG::Vector3f::operator*(const Vector3f &rhs)
• Add addr to singleton class headers and singleton members
  • Field::CollisionDirector
  • Field::CourseColMgr
  • Item::ItemDirector
  • Kart::KartObjectManager
  • System::CourseMap
  • System::KPadDirector
  • System::RaceConfig
  • System::RaceManager
  • System::ResourceManager
• Add description for System::RaceManager::STAGE_COUNTDOWN_DURATION
• Revise Kart::Hitbox header to use the @beginSetters/Getters aliases
• Add @file for Common.hh
• Add @brief for EGG::Mathf namespace
• Fix malformed descriptor for EGG::Quatf::dot(const Quatf &q) by moving to source file
• Added missing addresses to sSinCosTbl and sArcTanTbl

[malleoz]

Updated!