Add optional monolithic pakfile-based filesystem

[tehKaiN]

Description

Adds ability to read files from pak files while also maintaining typical file system reads. Also introduces pak_tool executable and packDirectory() convenience CMake function to generate those files.

Closes #50

Motivation and Context

This is crucial for floppy-based productions since Amiga file systems add their bloat when using a lot of small files. Having all of them condensed into a single one skips this overhead and allows for storing more data.

This also paves way for adding custom file handlers and implementing trackloaders as well as reading from virtual files stored in memory - thus bitmapLoadFromMemory() and similar functions are no longer needed.

It's also possible to add compression algorithms to the pak file and mark file as compressed (at all or with given algorithm) in pak file's table of contents.

The pak file structure is loosely based on Lost Vikings / Soul Reaver data files.

How Has This Been Tested?

Used in Battle Squadron 2 for AmiGameJam 2024.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

All functions which would open a file now accept opened file descriptor instead of file path - e.g. bitmapCreateFromFile() - in this example it is renamed to bitmapCreateFromPath() and the bitmapCreateFromFd() counterpart was introduced.

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.