Adds CHANGELOG file generated from github releases

[b-onc]

I've used this tool to create CHANGELOG

[buh]

How did you generate it?

[b-onc]

@buh Please see the PR description

[b-onc]

@tbarbugli The idea is to have a CHANGELOG we can keep updating. This repo did not have a chamgelog, but was using github releases for change logs. I've created the CHANGELOG so that we can continue using it (as we do in Chat repo)

The script used to generate the file is not in the PR, it'll not be included in the repo. It was a one time use.

[buh]

Please regenerate it. I updated the release notes.

[b-onc]

@buh Done