Docker related support enhanced

[mrunal4]

Commit related short descriptions:

• iniit_db.sql no more needed as database creation is handled in the docker-compose.yml and commented school_metric_data.sql content as it was just for testing as confirmed by Partha (Pardhu448)
• version changed as it was prompting version mismatch warnings for urllib3 and psycopg2
• To get command line arguments so that we can create users from scripts sliently (without user intervention/prompts). If arguments are missing it will prompt user for inputs
• Changed DB_HOST and DB_PORT values
• Check for - getting postgres up. Added : flask - init, migrate and upgrade along with admin user creation
• Added support for env variables in Dockerfile, .env files and config.py. .env files will be accessed by docker-compose.yml to set environment variables inside respective containers
• add ssl cert provision for gunicorn