Post-deploy configuration changes

[benlk]

As PRs get merged and deployed to staging, make notes here for items that will need to be configured on prod.

[benlk]

• [x] Add the code from https://github.com/INN/umbrella-energynewsnetwork/issues/73#issuecomment-585350704 to the Insert Headers and Footers plugin settings.

[benlk]

• [x] The widget addition as described in https://github.com/INN/umbrella-energynewsnetwork/pull/88

[benlk]

• [x] on the digest page, make sure that the feedback form is the last one in the sidebar: Subscribe, Manage, Feedback