#162634190 add validation and password hashing

[Benkimeric]

What does this PR do?

Hash user password during saving to the database
Add validation for empty fields
Add validation to the username to match case.

Description of Task to be completed?

Hash user password during saving to a database
Add validation for empty fields
Add validation to the username to match case.

How should this be manually tested?

• clone the repo
• git clone https://github.com/Benkimeric/iReporter-API.git
• create and activate the virtual environment
• virtualenv
• $source /bin/activate (in bash)
• install project dependencies by:
  $pip install -r requirements.txt
• python run.py or flask run
• Use postman to test the endpoints

Any background context you want to provide?

The tests written for editing a single record comment should pass on this code.

What are the relevant pivotal tracker stories?

#162634190

Questions:

Any feedback to improve on? Please advise.