Resolve "CSRF verification failed. (CSRF cookie when submitting forms)"

Closes #195

See merge request !201

Search update

See merge request !197

# Conflicts:
#   setup.py

Minor improvements on bin/dev

Closes #192 and #193

See merge request !199

Update document Installation

See merge request !198

Fix `memopol-code` alias so that the env variable `DJANGO_DEBUG` is
actually exported.

Fix typos, correct grammar and clarify some instructions in user
messages.

`memopol-update-all` was not working due to a typo in its definition.
Fixed.

When no shell is detected, set `RCSHELL` variable to point to
/dev/null.
This avoid weird error messages.

Shell detection used hardcoded paths that made it fail when using
distributions using a different scheme (e.g. debian-based distros).

Improve shell detection by using a glob-based comparison, where we do
not assume any specific path leading to the shell binary.

Deploy Django and docs in parallel

See merge request !196

Pipeline

See merge request !195

Development features

See merge request !192

Add informations about development setup

See merge request !193