Build and UI improvements

[trey-ivy]

This PR does the following:

Bazel Invocations View (/bazel-invocations)

• add user filter
• add result filter (client side)
• fix broken date picker for start time filter
• remove broken sort by from start time column
  

Bazel Builds view (/builds)

• store, add and display build timestamps
• add filter by to timestamps
  

Build Details view (/builds/[slug])

• if step label exists for an invocation, leverage that for display in the sidebar nav panel instead of the invocation id, otherwise if step label is empty, display the invocation id
• update panel header w/ build url and datetime
• remove 'envvars' component that only ever had the BUILD_URL in it
  

Tagline summary display cleanup for the invocation to use theme colors and be more readable

• wrap bazel command in a 'code' tag

• update test files and schema
• makefile