build: remove third party submodules

Most of these are extremely common in distributions now, so packagers
don't have much need for our in-tree versions - most don't even use them
as is

With our move to vcpkg for Windows/macOS, we also don't have a need for
them. So time to say goodbye!

Signed-off-by: Seth Flynn <getchoo@tuta.io>

libraries/README.md

@@ -10,14 +10,6 @@ See [github repo](https://github.com/FeralInteractive/gamemode).
 
 BSD-3-Clause licensed
 
-## cmark
-
-The C reference implementation of CommonMark, a standardized Markdown spec.
-
-See [github_repo](https://github.com/commonmark/cmark).
-
-BSD2 licensed.
-
 ## javacheck
 
 Simple Java tool that prints the JVM details - version and platform bitness.
@@ -99,22 +91,6 @@ Canonical implementation of the murmur2 hash, taken from [SMHasher](https://gith
 
 Public domain (the author disclaimed the copyright).
 
-## QR-Code-generator
-
-A simple library for generating QR codes
-
-See [github repo](https://github.com/nayuki/QR-Code-generator).
-
-MIT
-
-## libarchive
-
-Multi-format archive and compression library.
-
-See [github repo](https://github.com/libarchive/libarchive).
-
-BSD 2-Clause license with some exception.
-
 ## rainbow
 
 Color functions extracted from [KGuiAddons](https://inqlude.org/libraries/kguiaddons.html). Used for adaptive text coloring.
@@ -127,14 +103,6 @@ A Prism Launcher-specific library for probing system information.
 
 Apache 2.0
 
-## tomlplusplus
-
-A TOML language parser. Used by Forge 1.14+ to store mod metadata.
-
-See [github repo](https://github.com/marzer/tomlplusplus).
-
-Licenced under the MIT licence.
-
 ## qdcss
 
 A quick and dirty css parser, used by NilLoader to store mod metadata.