For crypt remote, use .go text files for encrypting foldernames/filenames algorithm

to enable experimenting with different foldername/filename encryption algorithms, to have rclone load the functions from a .go text file at runtime.

--filename-encryption-algorithm=/path/to/filename.go
--folder-encryption-algorithm=/path/to/foldername.go

in this way, we can all create and test new algorithms for encryption

while i am not at the level to write an entire remote and compile rclone, i can write functions in go.