Remove out-of-date projectile file

This commit removes an out-of-date projectile file from the top-level
directory.

Relates #28115

.projectile

@@ -1,31 +0,0 @@
--/target
--/core/target
--/qa/target
--/rest-api-spec/target
--/test-framework/target
--/plugins/target
--/plugins/analysis-icu/target
--/plugins/analysis-kuromoji/target
--/plugins/analysis-phonetic/target
--/plugins/analysis-smartcn/target
--/plugins/analysis-stempel/target
--/plugins/cloud-aws/target
--/plugins/cloud-azure/target
--/plugins/cloud-gce/target
--/plugins/delete-by-query/target
--/plugins/discovery-azure/target
--/plugins/discovery-ec2/target
--/plugins/discovery-gce/target
--/plugins/jvm-example/target
--/plugins/lang-expression/target
--/plugins/lang-groovy/target
--/plugins/lang-javascript/target
--/plugins/lang-python/target
--/plugins/mapper-murmur3/target
--/plugins/mapper-size/target
--/plugins/repository-azure/target
--/plugins/repository-s3/target
--/plugins/site-example/target
--/plugins/store-smb/target
--/plugins/target
--*.class