Request to merge AT5-370 branch with master

See merge request ska-telescope/csp-lmc-subelement!5

Changes to docs configuraiton files.

dependencies.

configuration from dsconfig file: if polling is enabled for the attributes,
the test on attribute reading is not performed because the value is read
from the cache and not from the device.
Polling has to be enabled into the dsconfig file when the real
devices are instantiated)

Fixed some bugs in device code.

command execution.

files.
Updated setup.cfg and setup.py.

First release of the sub-element master device.

Fix/remove pip

See merge request ska-telescope/templates/ska-python-skeleton!4

ST-281 CI metrics gathered.

See merge request ska-telescope/templates/ska-python-skeleton!3

ST-256 added some basic structure to the docs folder for automatic extraction of docstrings

See merge request ska-telescope/ska-skeleton!2

standardised code analysis with pylint

ST-85 Rename ska-skeleton to ska-python-skeleton

update Pipfile

- pipenv installs the environment fine
- we are now dependent on Nexus availability