Improve no storage message

[ferndot]

When no available storage methods exist, we display an error banner. Instead, we could display a positive "Set up a storage system" message and button. The button would call regions.nav('settings').

This would make it simpler for a new user to set up a storage.

[safwanrahman]

Can you please provide the Steps to Reproduce? @joshua-s

[ferndot]

1. Load Firetext in Firefox Nightly (https://github.com/codexa/firetext/wiki/Get-Coding#using-firefox-nightly)
2. Click the pen icon
3. There is a red, "no-storage-available" banner. (created by https://github.com/codexa/firetext/blob/develop/scripts/firetext.js#L260)

[ferndot]

@safwanrahman any luck reproducing this?