Need to add security headers and CORS policies

[DavidJCus]

**As a** service provider
**I need** my service to use security headers and CORS policies
**So that** my web site is not vulnerable to CORS attacks

#### Assumptions
* Flask-Talisman will be used for security headers
* Flask-Cors will be used to establish cross-origin resource sharing (CORS) policies

#### Acceptance Criteria
```gherkin
Given the site is secured
When a REST API request is made
Then secure headers and a CORS policy should be returned
```