* docs: add matrix space information and update readme
We recently created a Matrix Space which includes both the original room, and a new contributing room. This commit also performs some basic housekeeping on the README.md, including but not limited to: factorizing the security section, adjusting the main description, clearly outlining areas where help is wanted, adding information related to the helm chart, adding more details in the features summary, grammar, and misc other changes.
* docs: update security to be in line with the readme
Amir Zarrinkafsh
James Elliott
Clément Michaud