Bug#916985: reportbug: Adding --output flag to reportbug.conf, to save to file by default

[jonathan <jrubcop@gmail.com>]

Package: reportbug
Version: 7.5.1
Severity: wishlist
Tags: patch

I propose to support an option in reportbug.conf equivalent to the -o
flag, which outputs the email into a specified file instead of sending
it.

This would enable users who use an unsupported MUA to output the
formatted report to their drafts folder or other location and open it
in their unsupported MUA to continue authorship and submission. While
one can use the -o flag to accomplish this, including this option in
reportbug.conf can make the process happen by default.

My proposal was inspired by this article about using reportbug with
GNOME's Evolution program. 
https://blog.andresgomez.org/2017/02/28/how-to-use-debians-reportbug-with-evolution/#post-876

I have created an implementation of this proposal and submitted it to
reportbug's salsa repo. 
https://salsa.debian.org/reportbug-team/reportbug/merge_requests/12
This implementation simply modifies the config parser to accept
"outfile" tokens. The -o flag sets options.outfile anyway, so this
implementation is simple and works great.

I am actually using my modified version to submit this bug you're
reading now, as you can see my .reportbugrc contains an "outfile"
token, and I have used Evolution to send this bug report.

Should this config option be added to reportbug? If we decide yes, is
my implementation sufficient, or does it need work?

-- Package-specific info:
** Environment settings:
INTERFACE="urwid"

** /home/jonathan/.reportbugrc:
reportbug_version "7.5.1"
mode standard
ui urwid
email "jrubcop@gmail.com"
no-cc
smtphost reportbug.debian.org
outfile
/home/jonathan/.local/share/evolution/mail/local/.Drafts/new/reportbug-
mail.mbox

-- System Information:
Debian Release: buster/sid
  APT prefers testing
  APT policy: (990, 'testing'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.18.0-3-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US.utf8, LC_CTYPE=en_US.utf8 (charmap=UTF-8),
LANGUAGE=en_US.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages reportbug depends on:
ii  apt                1.8.0~alpha2
ii  python3            3.7.1-2
ii  python3-reportbug  7.5.1
ii  sensible-utils     0.0.12

reportbug recommends no packages.

Versions of packages reportbug suggests:
pn  claws-mail                                 <none>
pn  debconf-utils                              <none>
pn  debsums                                    <none>
pn  dlocate                                    <none>
pn  emacs24-bin-common | emacs25-bin-common    <none>
ii  exim4                                      4.91-9
ii  exim4-daemon-light [mail-transport-agent]  4.91-9
ii  file                                       1:5.34-2
ii  gnupg                                      2.2.11-1
ii  python3-urwid                              2.0.1-2+b1
pn  reportbug-gtk                              <none>
ii  xdg-utils                                  1.1.3-1

Versions of packages python3-reportbug depends on:
ii  apt                1.8.0~alpha2
ii  file               1:5.34-2
ii  python3            3.7.1-2
ii  python3-apt        1.7.0
ii  python3-debian     0.1.33
ii  python3-debianbts  2.7.2
ii  python3-requests   2.20.0-2

python3-reportbug suggests no packages.

-- no debconf information