Correct Earhtly setup file. Extend documentation on its use.

Remove preinstalled packages, and use the ones from pyproject instead.
Allow to use podman/docker on user choosing.

Earthfile

@@ -7,13 +7,10 @@ build:
     RUN apt update && apt install python3 python3-dev make python3-pip python3.10-venv libpcsclite-dev swig  -qy
     RUN apt install libusb-1.0-0-dev  -qy
     RUN python3 -m pip install -U pip
-    RUN python3 -m pip install -U flit pyusb cffi ecdsa intelhex nkdfu python-dateutil requests tqdm urllib3 tlv8
-    RUN python3 -m pip install -U "nrfutil >=6.1.4,<7"
-    RUN python3 -m pip install -U "spsdk >=1.7.0,<1.8.0"
-    RUN python3 -m pip install -U  "cryptography >=3.4.4,<37"
-
-
-    # COPY Makefile pynitrokey/ pyproject.toml README.md .
+    RUN python3 -m pip install -U flit
+    RUN mkdir pynitrokey
+    COPY pyproject.toml README.md .
+    RUN python3 -m flit install --only-deps
     COPY . .
     RUN make clean
     RUN make init

Makefile

@@ -20,12 +20,13 @@ init-fedora37:
 init: update-venv
 
 ARGS=
-.PHONY: run rune
+.PHONY: run rune builde
 run:
 	./venv/bin/nitropy $(ARGS)
 
+DOCKER=docker
 rune:
-	podman run --privileged --rm -it --entrypoint /bin/bash pynitrokey
+	$(DOCKER) run --privileged --rm -it --entrypoint /bin/bash pynitrokey
 
 builde:
 	earthly +build
@@ -146,4 +147,3 @@ wine-build/pynitrokey-$(VERSION).msi wine-build/nitropy-$(VERSION).exe:
 	bash build-wine.sh
 	#cp wine-build/out/pynitrokey-$(VERSION)-win32.msi wine-build
 	cp wine-build/out/nitropy-$(VERSION).exe wine-build
-

docs/developer-guide.rst

@@ -6,6 +6,25 @@ Setting Up The Environment
 
 Use ``make init`` to install ``pynitrokey``, its dependencies and the development tools inside a virtual environment in the ``venv`` folder.  This virtual environment is also used by other targets in the Makefile like ``make check``.  ``pynitrokey`` is installed in editable mode so that all changes to the source code also apply to the ``nitropy`` executable in the virtual environment.  If dependencies are changed, run ``make update-venv`` to update the virtual environment.
 
+
+By default the development environment is isolated using venv, when set up using ``make init``. To run the ``nitropy`` from there call ``./venv/bin/nitropy``. This can be used as a shortcut ``make run ARGS="nk3 list"``, where ``ARGS`` is an optional argument to pass to ``nitropy``.
+
+
+Containerized Environment
+--------------------
+
+Setting up a proper environment, matching the exact Python version, or having a newer one than it is supported, might be problematic for the development.
+For such cases it is handy to have development/test environment containerized, so it does not affect nor need changes in the host OS internals.
+For that Earthly tool is used, but any Docker-like tool will work.
+
+The common targets are listed in the main Makefile with the ``e`` suffix:
+
+- ``make builde`` - executes Earthly build process for the pynitrokey container image;
+- ``make rune`` - runs Docker container based on the pynitrokey image for a quick tests. Use ``DOCKER=podman`` to call ``podman`` binary instead of the default Docker.
+
+See https://earthly.dev/ for the Earthly setup instructions. Mind, that their binaries currently are not signed and cannot be verified, thus installation to the root directory of the host OS is not advised (on contrary to the claims on their main page). Use Dockerfile directly instead if in doubt.
+
+
 Linters
 -------
 

pynitrokey/conftest.py

@@ -1,10 +1,10 @@
 import logging
 import os
 import pathlib
-import secrets
 from functools import partial
 
 import pytest
+import secrets
 from _pytest.fixtures import FixtureRequest
 
 from pynitrokey.cli.nk3 import Context