DS: Updated changelog for v1

[zoharma]

This is a working PR to update the changelog for the release of the new DS.

Initial update:

• Looking at particular changes done for the DS and theming.

@akademy :

there are other things that need to be added too, outside of theming. Like new components, MUIv7, updated packages, new security checks, probably others.

[zoharma]

@akademy @VictoriaBeilsten-Edmands Please update and add the additional changes.