log-collector: update gc settings for es7

Java 14 removed CMS:

OpenJDK 64-Bit Server VM warning: Ignoring option UseConcMarkSweepGC; support was removed in 14.0
OpenJDK 64-Bit Server VM warning: Ignoring option CMSInitiatingOccupancyFraction; support was removed in 14.0
OpenJDK 64-Bit Server VM warning: Ignoring option UseCMSInitiatingOccupancyOnly; support was removed in 14.0

roles/log-collector/templates/elasticsearch/jvm.options

@@ -32,10 +32,9 @@
 ##
 ################################################################
 
-## GC configuration
--XX:+UseConcMarkSweepGC
--XX:CMSInitiatingOccupancyFraction=75
--XX:+UseCMSInitiatingOccupancyOnly
+-XX:+UseG1GC
+-XX:G1ReservePercent=25
+-XX:InitiatingHeapOccupancyPercent=30
 
 ## optimizations