SQL: Rename :core to :server in sql gradle files

Related to elastic/elasticsearch#28180

Original commit: elastic/x-pack-elasticsearch@375f437580

sql/cli/build.gradle

@@ -9,7 +9,7 @@ dependencies {
   compile project(':x-pack-elasticsearch:sql:shared-client')
   compile project(':x-pack-elasticsearch:sql:rest-proto')
   compile project(':x-pack-elasticsearch:sql:shared-proto')
-  compile project(':core:cli')
+  compile project(':server:cli')
 
   runtime "org.fusesource.jansi:jansi:1.16"
   runtime "org.elasticsearch:jna:${versions.jna}"

sql/rest-proto/build.gradle

@@ -3,7 +3,7 @@ description = 'Request and response objects shared by the cli and ' +
 
 dependencies {
   compile project(':x-pack-elasticsearch:sql:shared-proto')
-  compile (project(':core')) {
+  compile (project(':server')) {
     transitive = false
   }
   compile "org.apache.lucene:lucene-core:${versions.lucene}"