add(zmd): parse markdown file contents and display the parsed contents

Not everything can be parsed and displayed correctly yet, however this
will the default file format to use for adding page contents (i.e.
normal pages, blog entries, etc.)

build.zig.zon

@@ -31,6 +31,10 @@
             .url = "git+https://github.com/rockorager/libvaxis#e3062d62b60bf8a351f267a77e1a94e2614394aa",
             .hash = "1220479d09031168a100748e103ef5a8ffec5d4b0ff74a7e45cf2a9b09f82342b91f",
         },
+        .zmd = .{
+            .url = "git+https://github.com/jetzig-framework/zmd#90e52429cacd4fdc90fd615596fe584ae40ec8e9",
+            .hash = "12202a4edefedd52478223a44cdc9a3b41d4bc5cf3670497a48377f45ff16a5e3363",
+        },
     },
     .paths = .{
         "build.zig",