feat: read config.toml on program start

We just read it, don't actually parse any of the TOML.
Well, the library does, we just don't do anything /w it

.gitmodules

@@ -10,3 +10,6 @@
 [submodule "lib/zig-datetime"]
 	path = lib/zig-datetime
 	url = https://github.com/frmdstryr/zig-datetime
+[submodule "lib/zig-toml"]
+	path = lib/zig-toml
+	url = https://github.com/aeronavery/zig-toml