[Ref: create-readme] Readme file

[penpadstudio]

• build readme file for files
• add link to dropbox paper patterns
• add link to photoshop templates
• add link to sketch templates.

[penpadstudio]

• review to any examples already sent via campaign monitor for patterns enhancements
• review stats from campaign monitor for enhancements

[penpadstudio]

Will now be housed in wiki

[cehwitham]

@Pro-Paul We should still add a readme just introducing people to the repo and signposting to the right bits of the Wiki.

[penpadstudio]

@cehwitham I agree thats why I already did it and its waiting for a pull review =): https://github.com/NHSLeadership/nhs-email-templates/pull/57