Enable searching of issues based on Time Tracking values.

Enable searching issues based on time tracking fields through addition of a work ratio field/column.

The ratio of actual work vs estimated work is calculated for each issue and displayed in the issue navigator through a new "Work Ratio" column. This ratio is also added to the Lucene indexes in order to enable a range query on this value.

Hence, it will be possible to search for issues based on the ratio of actual work done against the original estimate of work required.