fix(*): encode db uri in xsweet

See merge request kotahi/kotahi!231

See #198. Also, provided a more friendly message if the reviewer (who is not an editor) hits the back button.

Closes #199

For #192.

For #192. Blockquote support may require changing to Wax editor. This xpub editor is a little buggy.

This was caused by increasing Node version to 15.

Closes #166

Also, prefer not to directly access process.env outside of custom-environment-variables.js