NEW PORT: shells/bashc: GNU Bourne Again shell extended with two-panel file manager

Bash Commander is a fork of GNU Bourne Again Shell. It's main feature is
a visual two-panel mode, much like Midnight Commander and other text-mode
visual shells.

WWW: https://github.com/sergev/bash-commander

Also add bashc to the CONFLICTS section of shells/bash.

PR: 253783, 253784
Submitted by: Igor Pokrovsky <ip AT unixway DOT org>