Add individual search page; Improvements to Highest Earners data view

[astrochun]

Closes #47 Fixes #56 Closes #61

Commit history:

• Load in unique_df in load_data function
• Add Individual Search to DATA_VIEWS
• Exclude fiscal year selection from Individual Search page
• Add EMPLOYMENT_COLUMN constant
• Add commons.format_salary_df function
• Add views.individual_search_page function
• Show common title, dept, college
• Add option to show year-to-year change
• Add sort alphabetically check box
• Minor tip at top of Individual Search page
• Remove unused code
• Use argparse to handle data from local or cloud source
• Use format_salary_df for currency formatting #61
• Set minimum salary for highest earner to $100k #56
• Minor fix with format_salary_df call
• Add option to select by campus or college #56
• Fix Highest Earners content with College selection
• Highest Earners: Handle lack of College data
• Highest Earners: strip College Name for College selection
• Update About content for new data views, changes
• Highest Earners: Change text from College to College/Division
• Use return null when College Name not available
• Update CHANGELOG.md for v1.0.0
• Bump version: v0.3.0 -> v1.0.0
• Update README.md with improvements