Added new search location for certificates and modified command that caused errors for Protonmail users.

If the password contains single quotes and is not surrounded by quotes,
Mutt removes the single quotes, rendering an incorrect password.

This patch puts the environment variable PREFIX in more use. If
specified, mull-wizard Makefile substitute all instances of prefix with
the provided environment variable.

Signed-off-by: Ayman Bagabas <ayman.bagabas@gmail.com>

In my [PR 224](https://github.com/LukeSmithxyz/mutt-wizard/pull/224), I
introduced a bug.  While I was catching SIGINT with the trap statement,
I did not actually exit the script and returned into the shell.

Fixes https://github.com/LukeSmithxyz/mutt-wizard/issues/234

The terminal text color  wasn't reset when the user  aborted the wizard
while being prompted for input.
This resolves https://github.com/LukeSmithxyz/mutt-wizard/issues/224

The current test  did not terminate  the script in cases  when the user
already has a private GPG key,  but they'd not initialized the password
store.
This leads to an infinite loop in the `getpass()` function.

The commit fixes https://github.com/LukeSmithxyz/mutt-wizard/issues/204

This allows mailsync to be called like this `bindsym $mod+e exec --no-startup-id mailsync; exec $term -e neomutt && pkill -RTMIN+12 i3blocks` such that it refreshes your mail when you open mutt without it needlessly syncing if a sync is already running.

Resolves https://github.com/LukeSmithxyz/mutt-wizard/issues/197.

Checking for a secret key with format `<foo@bar.com>` may not work for
people that store key IDs in .gpg-id. Removing the `<` and `>` makes it
work for both beople that use emails and people that use IDs.

If -a is passed along with "$@", mailsync will sync all mailboxes even
if only a single channel is passed in with "$@". This breaks the
semantics of the `o` macro in mutt which should only sync the current
mailbox that is currently being viewed in mutt.