Choose and sort the columns of Runs and Units

The Runs and Units lists showed a fixed set of columns, so checking a part number, a unit's secondary serial or its sub-units meant opening each row.

• Added a column picker at the right end of the table header on the Runs and Units lists, grouped like the filters, with every run and unit metadata key available as a column.
• Added sorting on every column that holds a single value, metadata included. Rows without a value always come last.
• Added a Sub-units column and a Contains Sub-Unit filter on Units, and a Unit Metadata filter on Runs.
• Improved long lists: the table header now stays visible while you scroll.
• Fixed the Units search being ignored when sorting by part number, last run or last procedure.