compress: Add gzip module & refactor compress & compress.zlib module (#14599)

vlib/compress/gzip/gzip_test.v

@@ -0,0 +1,8 @@
+module gzip
+
+fn test_gzip() ? {
+	uncompressed := 'Hello world!'
+	compressed := compress(uncompressed.bytes())?
+	decompressed := decompress(compressed)?
+	assert decompressed == uncompressed.bytes()
+}