[Fix] Updated README.rst

[viniarck]

Updated readme, following the same pattern as we have for mef_eline and flow_manager

• Intentionally didn't add the |Stable| shield yet since there are some important well known issues that we haven't prioritized
• Removed requirements section since on setup.py develop it's installing the dependencies (same as we have on other napps)
• Added banner
• Documented existing published events