Bug 26433: Add Control number to SRU field configuration

Bug 26433: Add Control number to SRU field configuration

This simply adds a row to the config page for configuring a mapping for Control
number, without this patch you cannot configure the feild, and the default is 'any'

I used the first record here for testing:
http://lx2.loc.gov:210/NAF?operation=searchRetrieve&version=1.1&query=query=bath.personalName=%22butler%20octavia%22&maximumRecords=20&recordSchema=marcxml

Enter SRU server using settings here:
https://www.loc.gov/z3950/lcserver.html#serv
       host: lx2.loc.gov
       port: 210
         db: NAF
     userid:
   password:
 servername: LOC SRU
    checked: NULL
       rank: NULL
     syntax: USMARC
    timeout: 0
 servertype: sru
   encoding: utf8
 recordtype: authority

To test:
1 - Setup SRU server using settings above
2 - In the server config click 'Modify' under 'SRU search fields mapping'
3 - Note you don't have an option for 'Control number'
4 - Go to Authorities
5 - New from Z39.50/SRU
6 - Search 'Control number' field with: PS3552.U827
7 - You get the record noted above as all fields are searched
8 - Search 'Control number' field with: 79056654
9 - You get the record noted above as all fields are searched
10 - Apply patch
11 - In the server config click 'Modify' under 'SRU search fields mapping'
12 - Note you now have a config for 'Control number'
13 - Enter 'bath.lccn'
14 - Save
15 - Repeat search from #6 - no result
16 - Repeat search from #8 - correct result as only lccn fields are search
17 - Modify server config ans set 'Control number' to 'bath.lcCallNumber'
18 - Repeat search from #6 - correct results as call number field is now search
19 - Repeast search from #8 - no result

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>