[Docs] Remove Kerberos/SPNEGO Shield plugin (#28019)
[Docs] Remove Kerberos/SPNEGO Shield plugin (#28019)

Plugin has not been updated in over two years and requires Shield and ES 2.3.1
gingerwizard/elasticsearch,nknize/elasticsearch,nknize/elasticsearch,rajanm/elasticsearch,scottsom/elasticsearch,coding0011/elasticsearch,kalimatas/elasticsearch,gingerwizard/elasticsearch,gfyoung/elasticsearch,coding0011/elasticsearch,scottsom/elasticsearch,coding0011/elasticsearch,gfyoung/elasticsearch,HonzaKral/elasticsearch,uschindler/elasticsearch,gingerwizard/elasticsearch,gfyoung/elasticsearch,qwerty4030/elasticsearch,robin13/elasticsearch,kalimatas/elasticsearch,HonzaKral/elasticsearch,scorpionvicky/elasticsearch,scorpionvicky/elasticsearch,gfyoung/elasticsearch,scorpionvicky/elasticsearch,qwerty4030/elasticsearch,fred84/elasticsearch,uschindler/elasticsearch,nknize/elasticsearch,scottsom/elasticsearch,rajanm/elasticsearch,robin13/elasticsearch,rajanm/elasticsearch,robin13/elasticsearch,qwerty4030/elasticsearch,kalimatas/elasticsearch,HonzaKral/elasticsearch,uschindler/elasticsearch,fred84/elasticsearch,gingerwizard/elasticsearch,uschindler/elasticsearch,GlenRSmith/elasticsearch,fred84/elasticsearch,coding0011/elasticsearch,s1monw/elasticsearch,scorpionvicky/elasticsearch,gingerwizard/elasticsearch,kalimatas/elasticsearch,s1monw/elasticsearch,GlenRSmith/elasticsearch,robin13/elasticsearch,gingerwizard/elasticsearch,HonzaKral/elasticsearch,GlenRSmith/elasticsearch,scorpionvicky/elasticsearch,fred84/elasticsearch,gfyoung/elasticsearch,rajanm/elasticsearch,scottsom/elasticsearch,gingerwizard/elasticsearch,GlenRSmith/elasticsearch,uschindler/elasticsearch,s1monw/elasticsearch,rajanm/elasticsearch,s1monw/elasticsearch,s1monw/elasticsearch,scottsom/elasticsearch,fred84/elasticsearch,GlenRSmith/elasticsearch,rajanm/elasticsearch,robin13/elasticsearch,nknize/elasticsearch,qwerty4030/elasticsearch,nknize/elasticsearch,qwerty4030/elasticsearch,coding0011/elasticsearch,kalimatas/elasticsearch