LibCore: Add support for application/zip mime-type

The local file header signature of a ZIP entry is normally 0x04034B50
and stored in little-endian byte order. Therefore, if the archive
starts with an entry we can identify a ZIP file by checking if the
first two bytes are 0x504B (PK).

Also checks for the .zip file extension, which is is also used by file
if no byte signature was detected.

Userland/Libraries/LibCore/MimeData.cpp

@@ -78,6 +78,8 @@ String guess_mime_type_based_on_filename(StringView path)
         return "application/javascript";
     if (path.ends_with(".json", CaseSensitivity::CaseInsensitive))
         return "application/json";
+    if (path.ends_with(".zip", CaseSensitivity::CaseInsensitive))
+        return "application/zip";
     if (path.ends_with(".md", CaseSensitivity::CaseInsensitive))
         return "text/markdown";
     if (path.ends_with("/", CaseSensitivity::CaseInsensitive))
@@ -120,6 +122,7 @@ String guess_mime_type_based_on_filename(StringView path)
     __ENUMERATE_MIME_TYPE_HEADER(shell, "text/x-shellscript", 0, 10, '#', '!', '/', 'b', 'i', 'n', '/', 's', 'h', '\n')                          \
     __ENUMERATE_MIME_TYPE_HEADER(sqlite, "extra/sqlite", 0, 16, 'S', 'Q', 'L', 'i', 't', 'e', ' ', 'f', 'o', 'r', 'm', 'a', 't', ' ', '3', 0x00) \
     __ENUMERATE_MIME_TYPE_HEADER(tar, "application/tar", 0x101, 5, 0x75, 0x73, 0x74, 0x61, 0x72)                                                 \
+    __ENUMERATE_MIME_TYPE_HEADER(zip, "application/zip", 0, 2, 0x50, 0x4B)                                                                       \
     __ENUMERATE_MIME_TYPE_HEADER(tiff, "image/tiff", 0, 4, 'I', 'I', '*', 0x00)                                                                  \
     __ENUMERATE_MIME_TYPE_HEADER(tiff_bigendian, "image/tiff", 0, 4, 'M', 'M', 0x00, '*')                                                        \
     __ENUMERATE_MIME_TYPE_HEADER(wasm, "application/wasm", 0, 4, 0x00, 'a', 's', 'm')                                                            \