Add py3-* stub ports required for the upcoming finance/electrum update to 3.0.1

[ehaupt]

Summary

I'd like to update finance/electrum to 3.0.1 which has switched from qt4/python2.7 to qt5/python3. This update requires the presence of a few py3-* stub ports. The pre-commit hook currently prevents me from committing those.

I'd like to add the following ports:

• devel/py3-protobuf
• security/py3-pbkdf2
• security/py3-pyaes
• textproc/py3-qrcode
• www/py3-httplib2

Test Plan

poudriere testport: OK

[bdrewery]

Approved by: portmgr (bdrewery)