Sovrin-Node: Python interpreter is not executed in Optimise mode

Sovrin-Node is started via the ubuntu service file

/etc/systemd/system/sovrin-node.service

However the python interpreter is not started in Optimise mode it is running in the default 'DEBUG' mode

The entry point python script should be executed with the '-O' option which will ensure it is running in optimised mode.

This will have 2 side effects:

1. Strip all assert statements. This trades defense against corrupt program state for speed.
2. Strip all docstrings. So a wee bit of saving on memory requirment

So when triaging we need to consider the bullet # 1, do we want to play safe. Asserts are probably going still crash the program.