DRILL-6879: Show warnings for potential performance issues
1. Introduced warning for non-progressive fragments. Based on a threshold (`drill.exec.http.profile.warning.progress.threshold`), if all fragments have not made progress within that time, a warning is issued. The default is 5 minutes (300 sec)
2. Introduced a warning if any of the buffered operators spill to disk.
3. Introduced a warning for operators where the longest running fragment runs beyond a minimum threshold (drill.exec.http.profile.warning.time.skew.min), and runs atleast 2 times longer than the average (drill.exec.http.profile.warning.time.skew.ratio.process). The clock symbol with a tooltip indicates the extent of the skew. For wait times, the ratio is defined by `drill.exec.http.profile.warning.time.skew.ratio.wait`
3. Introduced a warning for operators where the average wait time of a scan operator exceeds its processing time, for a minimum threshold (drill.exec.http.profile.warning.scan.wait.min). The turtle symbol with a tooltip indicates which scan operator spent more time waiting than processing.
4. TableBuilder Refactored
a. Using attribute map instead of String arguments, eg. for 'title'
b. Removed APIs that pass a hyperlink since that is never used.
closes #1572
