Switch to chart.js (improved style + bug fixes)

[alexgleason]

I've built off of #16 here, but fixed a couple bugs:

• Properly align containers along the left edge
• Pagination works correctly now
• Pagination buttons become deactivated at the start and end of the pages
• The chart is smaller
• Use only 4 ticks along the X axis to match the previous version
• Switch to dates instead of day of the week on the X axis
• Properly label the dataset in the tooltip ("Sessions")
• Increase vertical space between parts of the page, especially useful for mobile
• Change page title to just "Analytics" and include the bar chart icon
• Make the left column of the table expand as much as possible so it doesn't awkwardly resize when changing pages
• Move the buttons up into the page header

[alexgleason]

Forgot to mention: I'll add my date range thing in a separate PR. I reverted back when I noticed this issue was still open because I wanted to address it first before building more on top of it.