Package Electrum-NMC in distros' package repos

[JeremyRand]

It would be useful to package Electrum-NMC in various distros' package repos.

• Electrum-NMC status on Repology.
• Upstream Electrum status on Repology.

Sub-tickets:

• https://github.com/namecoin/electrum-nmc/issues/120

Hacktoberfest participants:

• https://github.com/namecoin/meta/issues/77