Make the changelog one aggregated file, update and refer to that file in each release

[louispt1]

Context

Each release contains a technical changelog which is an accumulation of the changes from the beginning of the year.

The changelog should instead represent all changes from all time. Each deploy we can update the overarching changelog, rather than adding another csv that duplicates some information.

Current shortcoming

Duplicated information among many csvs in the releases.

Proposed enhancement

One csv holding all changes for all time.

Also:

• Update the changelog skills, any releases documentation etc