Ben: μBenchmark archival

• Description

TODOs

• Do not assume that the code is under a jiri project (i.e., detect ben.SourceCode based on the git repository state?)
• Page to list out all benchmark results (across all scenarios) for a particular (BenchmarkName, SourceCode) pair (e.g., results for foo/bar.BenchmarkBaz across linux, darwin, arm, amd64 for a particular snapshot of the code)
• Render times in local timezone (and convert timezones in the query to the server)
• Ability to query results by time range