Documentation: Add username/password parameters for basic auth (elastic/x-pack-elasticsearch#4126)
Documentation: Add username/password parameters for basic auth (elastic/x-pack-elasticsearch#4126)

relates elastic/x-pack-elasticsearch#4070

Original commit: elastic/x-pack-elasticsearch@19d7002d3c0481ed444d7a778a55161bbe06e64f

GlenRSmith/elasticsearch,gingerwizard/elasticsearch,coding0011/elasticsearch,gingerwizard/elasticsearch,gingerwizard/elasticsearch,gingerwizard/elasticsearch,GlenRSmith/elasticsearch,uschindler/elasticsearch,HonzaKral/elasticsearch,HonzaKral/elasticsearch,uschindler/elasticsearch,gfyoung/elasticsearch,robin13/elasticsearch,scorpionvicky/elasticsearch,nknize/elasticsearch,gingerwizard/elasticsearch,uschindler/elasticsearch,coding0011/elasticsearch,GlenRSmith/elasticsearch,gingerwizard/elasticsearch,uschindler/elasticsearch,scorpionvicky/elasticsearch,nknize/elasticsearch,robin13/elasticsearch,coding0011/elasticsearch,GlenRSmith/elasticsearch,uschindler/elasticsearch,scorpionvicky/elasticsearch,HonzaKral/elasticsearch,HonzaKral/elasticsearch,gfyoung/elasticsearch,coding0011/elasticsearch,coding0011/elasticsearch,gfyoung/elasticsearch,scorpionvicky/elasticsearch,nknize/elasticsearch,nknize/elasticsearch,nknize/elasticsearch,scorpionvicky/elasticsearch,gfyoung/elasticsearch,robin13/elasticsearch,gingerwizard/elasticsearch,robin13/elasticsearch,robin13/elasticsearch,gfyoung/elasticsearch,GlenRSmith/elasticsearch