Make command line interface (cli) available via Python '-m' switch

[eneelo]

Adds hook for command line interface (qats.cli.main()), making it accessible by using the Python command line option '-m'. Examples of command line syntax that is now supported:

python -m qats --help
python -m qats app 
python -m qats config --link-app

Note that the old syntax for invoking cli is still supported (e.g., qats app to launch GUI).

This PR also adds a new option to the cli config:

python -m qats config --link-app-no-exe

This adds a shortcut for running the qats app (GUI) in the Windows start menu. This is similar to the existing --link-app option, with the difference that --link-app-no-exe creates a shortcut that launches the GUI by utilizing the new cli hook (i.e., runs pythonw -m qats app) instead of launching the GUI entry point created by setuptools. This is convenient if unsigned executables are blocked by IT security policies.

[HOLD] Changelog is now rendered as part of Sphinx documentation, making it available at https://qats.readthedocs.io/en/latest/changes.html.

Todo:

• [x] Add note in Sphinx documentation.
• [x] Sphinx docs: fix API contents depth.
• [x] Add note in README.md

[eneelo]

@tovop: I found a way to render the changelog as part of the Sphinx documentation without duplicating CHANGELOG.md or its contents. I find this useful, to serve more or less as release notes on Readthedocs. One counter-argument is that parts of the changelog may be relevant only from a development perspective, although I find that it mostly includes information relevant also to end-users. Let me know what you think about this 'twist' when (if) you have time to look at it.

[sonarcloud[bot]]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
3 Code Smells

No Coverage information
0.0% Duplication