Save timeline data as JSON rather than a javascript file

[rwstauner]

This simplifies the data and allows us to use it for other functions.

• Skip duplicates more generically so we can remove the config key
• Lookup "human name" for the timelines that use it
• Remove unused items from the data we write for the timelines
• Move "selected benchmarks" array to the only report that uses it
• Remove exclusion array for benchmark that no longer exists
• Move time format to a constant and make the format more normal
• Calculate time range in js
• Calculate the value range in the js
• Output json instead of using ERB to generate javascript
• Fix class name
• Simplify further by just sending the config root