Reuse the Metafacture Core .gitignore

https://github.com/metafacture/metafacture-core/blob/master/.gitignore

It is nicely formatted and added the files from the old .gitignore that were missing.

.gitignore

@@ -1,8 +1,64 @@
+#
+# Copyright 2017, 2018 Christoph Böhme
+#
+# Licensed under the Apache License, Version 2.0 the "License";
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+# Ignore temporary maven files:
+target/
+
+# Ignore temporary gradle files:
 .gradle/
+.gradletasknamecache
 build/
+bin/
+
+# Ignore tmp directory
+tmp
+
+# Ignore Eclipse project files:
+.checkstyle
+.pmd
+.eclipse-pmd
+.classpath
+.project
+.settings/
+
+# Ignore IntelliJ project files:
+*.ipr
+*.iws
+*.iml
+.idea
+out/
+/out/
+/*/out/
+
+# Ignore IntelliJ JIRA plugin
+atlassian-ide-plugin.xml
+
+# Ignore files generated by CI:
+buildbot.keyring
+
+# Ignore VS code/codium config files
+.vscode
+
+# Ignore files with sensitive data
+gradle.properties
+secring.gpg
+
+# Others
 generated/
 xtext-gen/
-out/
 node_modules/
 xtext-server/
 package-lock.json