Fix socket.timeout issue #8

Fix for issue ZuinigeRijder/SolisCloud2PVOutput#8

• catch socket.timeout and any other exception
• increase timeout from 10 to 30 (seconds)

Fixed problem when PVOutput returns NaN for voltage

Solved issue #3

• When voltage is NaN take previous voltage
• Wait till next 5 minutes interval plus 3 minutes to have possibly faster results

Increased sending retries, endless retry getting data, small improvements

• increased sending retries to 30 minutes
• endless retry getting data
• improved function naming and return value typing

API Secrets configuration moved out of python script into .cfg file

Change your API SECRETS in the configuration file "combine_two_pvoutput_systems.cfg". This way a new python script will not overwrite your API SECRETS.

First release

• less logging
• added TODAY constant as yyyymmdd to compute it only once
• made pylint compliant
• make flake8 and black linters compliant
• fixed endless loop when no results in read in memory