Platform Training and Quiz 2

[harryface]

This is for the on platform training 2.

It was a vey big PR and creating this as a way to break it into bits.

This Platform Training 1:

• Created a new training app, with its model, admin, fixtures etc

The Part 2 will be having this as a Parent and will contain the logic:

• Population of Training, its quiz and content body via JSON.
• On major version change, sets all older version training to 30 days expiry, and sends a mail to users.
• The views logic for displaying and undergoing the training.

[superryeti]

Closing this because we decided to open two new PRs with simplified and squashed commits

PR 1: Add create training from admin console by uploading json
#1950

PR 2: implement take training feature and resume training feature for user
#1951