Store each CSP rule on a seperate line in config

Problem/Motivation

When performing git diffs on seckit.setting it's very hard to see changes when all the lines are so long.
If each item was on it's own line it would be easy to see additions, deletions and changes.
It would also be much easier to spot any duplicate rules.

Steps to reproduce

Current config example:

default-src: '''self'' blob: *.local-d8.my127.site *.brightcove.net *.brightcove.com *.boltdns.net *.typekit.net *.nr-data.net *.buyatab.com *.mysite.com *.quantummetric.com cloud.typography.com  ''unsafe-inline'' ''unsafe-eval'''

Suggested config example:

default-src:
  - '''self'''
  - 'blob:'
  - '*.local-d8.my127.site'
  - '*.brightcove.net'
  - '*.brightcove.com'
  - '*.boltdns.net'
  - '*.typekit.net'
  - '*.nr-data.net'
  - '*.buyatab.com'
  - '*.mysite.com'
  - '*.quantummetric.com'
  - 'cloud.typography.com'
  - '''unsafe-inline'''
  - '''unsafe-eval'''

Proposed resolution

Update yaml config sample.