Add batch replay functionality

[malleoz]

In KReplaySystem::parseOptions, I propose that we either let the user pass in -ghost followed by a variable number of arguments each being a filepath, or pass in -batch with a directory path. Then we can modify the class as follows:

• Create a new struct as follows:

struct GhostMetadata {
    const char *m_fileName;
    const u8 *m_data;
    size_t m_size;
};

• Instead of m_currentXXX, implement a std::queue<GhostMetadata> m_ghosts such that the current ghost is always the ghost at the front of the queue
• When passing in multiple ghosts or a directory, they are added to this queue
• Need a lot of changes so that we don't quit out when first ghost is done. i.e. KReplaySystem::run() will need to be re-worked.
• When a simulation is complete, pop the ghost from the queue, call changeScene or whatever else we need, and start simulating the new ghost.

[malleoz]

On second thought, @vabold it might make more sense to have a new batch class

class KBatchReplaySystem final : public KReplaySystem

This way, the batch class can observe the return of KReplaySystem::run and then re-init the replay system to a new ghost. We could put the std::queue in KBatchReplaySystem, and when we pop from the queue, we put that ghost as the KReplaySystem's current ghost. I also like this approach because we can redefine parseOptions.