webstaff: Z39.50 search and import interface

webstaff: Z39.50 search and import interface

- fetch configured Z39.50 targets
- can now select targets
- search field form now active
- can now retrieve results
- check for empty query correctly
- retain reference to target list
- preserve search query input when toggling Z39.50 target selection
- implement clear form handler
- allow enter key to submit search
- track index of Z39.50 results so that individual ones can be selected
- note results of experiences to make the title be conditionally a hyperlink
- implement show in catalog
- implement direct import
Signed-off-by: Galen Charlton <gmc@esilibrary.com>