This BUILD.md was merged into main without updating qa.py to reflect it
because our linters were down due to the now-fixed poetry bug (see prev
commit).
Narrow down the system packages that we install in dev environments. The
rationale is that we get most of the Python dependencies from Poetry, so
we don't need to install them from the system as well.
The packages that we do need to install are non-Python ones, and this
commit adds some that were missing: make, python3-stdeb. Also, we
explicitly install the base Qt5 libraries, in order to get the graphics
and C++ libraries that we can't get from PyPI.
Add a script that makes the user go through the QA steps for a supported
Dangerzone platform, and may optionally run them automatically, if the
user agrees.
Closes#287