First readme update

[sebastianbarry]

docker/load_mongodump.sh

• Added the load_mongodump.sh file from e-mission/em-public-dashboard

README.md

• Reordered the Docker method to go at the top of the How to run this app section
• Added a "How to load data into the app" section

[sebastianbarry]

@shankari @swastis10 adding you both for visibility