Add contributing docs on venv

[bdovaz]

Fixes #4465

[github-actions]

🦙 MegaLinter status: ⚠️ WARNING

Descriptor	Linter	Files	Fixed	Errors	Elapsed time
✅ API	spectral	1		0	1.75s
⚠️ BASH	bash-exec	6		1	0.05s
✅ BASH	shellcheck	6		0	0.19s
✅ BASH	shfmt	6	0	0	0.03s
✅ COPYPASTE	jscpd	yes		no	3.58s
✅ DOCKERFILE	hadolint	129		0	23.09s
✅ JSON	jsonlint	20		0	0.26s
✅ JSON	v8r	22		0	16.27s
⚠️ MARKDOWN	markdownlint	267	0	301	24.59s
✅ MARKDOWN	markdown-table-formatter	267	0	0	161.26s
⚠️ PYTHON	bandit	214		66	3.37s
✅ PYTHON	black	214	0	0	3.99s
✅ PYTHON	flake8	214		0	1.98s
✅ PYTHON	isort	214	0	0	0.63s
✅ PYTHON	mypy	214		0	17.9s
✅ PYTHON	pylint	214		0	34.46s
✅ PYTHON	ruff	214	0	0	0.05s
✅ REPOSITORY	checkov	yes		no	35.24s
✅ REPOSITORY	git_diff	yes		no	0.04s
⚠️ REPOSITORY	grype	yes		26	13.42s
✅ REPOSITORY	secretlint	yes		no	9.75s
✅ REPOSITORY	trivy	yes		no	16.74s
✅ REPOSITORY	trivy-sbom	yes		no	0.29s
⚠️ REPOSITORY	trufflehog	yes		1	53.06s
✅ SPELL	cspell	717		0	13.99s
⚠️ SPELL	lychee	349		14	9.97s
✅ XML	xmllint	3	0	0	0.03s
✅ YAML	prettier	160	0	0	3.21s
✅ YAML	v8r	102		0	31.49s
✅ YAML	yamllint	161		0	2.46s

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