#!/bin/bash
string="name: MAIN_ROLE
description: ROLE DESCRIPTION
readOnly:
roleReferences:
- roleTemplateAppId: app1
  roleTemplateName: template1
  name: Name1
- roleTemplateAppId: app2
  roleTemplateName: template2
  name: Name2
"
awk 'NR==1{               # When on Line 1
    a=$2;cnt=0            # Set a and cnt vars
}
/^-/{                     # When line starts with -
    rta[cnt]=$3; getline; # Add role template app ID to rta array
    rtn[cnt]=$2; getline; # Add role template name to rtn array
    n[cnt]=$2;cnt++       # Add name to n array
}
END{                      # When the file processing is over
    for(i=0;i<cnt;i++) {  # Iterate over the found values and... 
        print a","n[i]","rtn[i]","rta[i]  # print them
    }
}' <<< "$string"

# => MAIN_ROLE,Name1,template1,app1
#    MAIN_ROLE,Name2,template2,app2