Change the `history` config block's name to `output`, deprecating `history`

The label for the section in the application config that designates document-level settings, now called `history`, is confusing. Deprecate `history` but maintain support for it until 1.0 release, in favor of `output`. These are settings that govern an entire document and cascade down to potential sections `notes` and `changelog`.

This change involves modifying all test and demo configurations accordingly.

## Release Note

The `history` section key in the application configuration file has been changed to `output`. While `history` will remain supported until the 1.0 version of ReleaseHx, all users should switch to `output`. This key name better expresses the properties under its label.