Docs: Update sections about sorting in various table/grid interfaces

In the 2.11 docs, there was a documentation chapter called "Sorting Columns". That content would be useful in the web client docs, but it needs to be reviewed for accuracy with the new interface.

"Sorting" chapter from 2.11 docs:
http://docs.evergreen-ils.org/2.11/_sorting_columns.html

Suggested tasks:
  - Merge generic content into "Column Picker" section (http://docs.evergreen-ils.org/dev/_column_picker.html).
  - Merge "Pull list" content into "Display Hold Types on Pull Lists".
  - Merge "circ policy" content into circ policy docs.