Add validation for Financial Reports

Prepare for users inputting data rather than script
Change from has_one to the correct belongs_to
Check for numerical values in year,spending, funding
Create Financial Report Admin Pages

Provide new, edit, update, delete
Add tests for FinancialReport

Add factory for a FinancialReport
Add unit tests for FinancialReport
Add functional tests for Financial Reports Admin Interface
Merge pull request #733 from ElliotJH/public-bodies-editable

Make Public Bodies Financial Reports Editable

https://www.pivotaltracker.com/s/projects/367813/stories/54429268