Improve stop/start behavior of DB's related functions

[BraulioV]

Related issue
closes #1057

Description

This PR adds a new decorator that simplifies the creation of mocking functions.

Configuration options

NA

Logs example

# python3 -m pytest test_scan_results/test_scan_*
============================================================================================== test session starts ==============================================================================================
platform linux -- Python 3.6.8, pytest-5.4.2, py-1.8.1, pluggy-0.13.1
rootdir: /tmp/wazuh-qa/tests/integration, inifile: pytest.ini
plugins: metadata-1.9.0, html-2.0.1, testinfra-5.0.0
collected 31 items

test_scan_results/test_scan_different_cves.py .........                                                                                                                                                   [ 29%]
test_scan_results/test_scan_nvd_feed.py .............                                                                                                                                                     [ 70%]
test_scan_results/test_scan_providers_and_nvd_feed.py .........                                                                                                                                           [100%]

======================================================================================== 31 passed in 323.20s (0:05:23) =========================================================================================

Tests

• Proven that tests pass when they have to pass.
• Proven that tests fail when they have to fail.

• Python codebase satisfies PEP-8 style style guide. pycodestyle --max-line-length=120 --show-source --show-pep8 file.py

[spothound]

awesome!