Update README-SNAP.md Added section on weatherreport

[sklassen]

Weatherreport under snap works, it just needs some extra parameters.

Overview

Main issue is that default.ini is missing from the /var/snap/couchd/current/etc. But weatherreport also needs to know the configuration directory and the default message level notice only shows exceptions.

Testing recommendations

Ran the bash example on a fresh snap installation.

Checklist

• [X] Code is written and works correctly;
• [X] Changes are covered by tests;
• [X] Documentation reflects the changes;