LibWasm: Start implementing a basic WebAssembly binary format parser

This can currently parse a really simple module.
Note that it cannot parse the DataCount section, and it's still missing
almost all of the instructions.
This commit also adds a 'wasm' test utility that tries to parse a given
webassembly binary file.
It currently does nothing but exit when the parse fails, but it's a
start :^)

Userland/Utilities/wasm.cpp

@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2021, Ali Mohammad Pur <mpfard@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibCore/ArgsParser.h>
+#include <LibCore/File.h>
+#include <LibCore/FileStream.h>
+#include <LibWasm/Types.h>
+
+int main(int argc, char* argv[])
+{
+    const char* filename = nullptr;
+
+    Core::ArgsParser parser;
+    parser.add_positional_argument(filename, "File name to parse", "file");
+    parser.parse(argc, argv);
+
+    auto result = Core::File::open(filename, Core::IODevice::OpenMode::ReadOnly);
+    if (result.is_error()) {
+        warnln("Failed to open {}: {}", filename, result.error());
+        return 1;
+    }
+
+    auto stream = Core::InputFileStream(result.release_value());
+    auto parse_result = Wasm::Module::parse(stream);
+    if (parse_result.is_error()) {
+        warnln("Something went wrong, either the file is invalid, or there's a bug with LibWasm!");
+        return 2;
+    }
+
+    return 0;
+}