1.13.0: Properly collect coverage on azure

(cherry picked from commit d1c92f8997ef898b97aa2b117fd7ef5f279c6c7e)

better coverage: remove useless lines from abstract methods, branches

(cherry picked from commit a47b657ef52bb2e4422f8c9e4b070c39b8ae4b83)

use libyaml pyyaml, when it possible

(cherry picked from commit 66a8e5bb7ddf38da1fdd6902a5b95eada8686fe7)

fix bandit checker

(cherry picked from commit 32022ad6e9fec186d91c71579fd4caf8758da0d1)

rename ssh connection logger to separate from logger path

(cherry picked from commit c6f9705fc9d75ee45499eea76bdc8f266f334669)

Properly work with isfile/isdir/islink

* add islink
* add symlink (`os.symlink` mimic)
* add chmod (`os.chmod` mimic)

(cherry picked from commit 5e9bea3cb29563432e268efc621487ddad9e8ec7)

Fix pylint warnings: install isort with toml support