[arch-dev-public] Replacing pycrypto with pycryptodome

Antonio suggested on IRC to drop pycrypto in favor of pycryptodome. The latter is "an almost drop-in replacement for the old PyCrypto library" according to its documentation. pycrypto has been unmaintained for several years. [1] Unless someone objects in the next few days, I'll proceed to drop python-crypto and add replaces=() to python-pycryptodome. [1] https://github.com/dlitz/pycrypto/issues/173