Add provider to retrieve content

[sggerard]

Update Angular frontend with a provider to pull Content from the chosen CMS using either a REST or GraphQL API. Ensure provider is reusable across all content pages and pages are not rendered until content has been retrieved.

[sggerard]

Installed the GraphQL plugin on Strapi and the Apollo library on the BCMI front end to use GraphQL to fetch content from the CMS. Wrote a query extension in Strapi and a Anguler resolver to fetch the page content for the current route (url).