utils: add IsURI(), GetURIScheme()
utils: add GetURIContent(), update EncodeURI() and DecodeURI()
utils: update IsFileExist(), if is uri path, ensure it decoded
utils: update URIToPath(), PathToURI()
utils: refactor code, rename EnsureDirExist()
utils: add IsDir(), IsSymlink()
utils: update CopyFile()
utils: add GenUuid(), RandString()
utils: add IsInterfaceNil()
utils: fix DecodeURI() issue, do not decode if is not uri
utils: revert URIToPath() and PathToURI()