Restore branch and git sha, to use it in logs and in rageshakes.

Remove quite useless `gitRevisionDate`.

plugins/src/main/kotlin/extension/Utils.kt

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2022 New Vector Ltd
+ *
+ * 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.
+ */
+
+package extension
+
+import org.gradle.api.Project
+import java.io.ByteArrayOutputStream
+import java.io.IOException
+
+private fun Project.runCommand(cmd: String): String {
+    val outputStream = ByteArrayOutputStream()
+    val errorStream = ByteArrayOutputStream()
+    project.exec {
+        commandLine = cmd.split(" ")
+        standardOutput = outputStream
+        errorOutput = errorStream
+    }
+    if (errorStream.size() > 0) {
+        println("Error while running command: $cmd")
+        throw IOException(String(errorStream.toByteArray()))
+    }
+    return String(outputStream.toByteArray()).trim()
+}
+
+fun Project.gitRevision() = runCommand("git rev-parse --short=8 HEAD")
+
+fun Project.gitBranchName() = runCommand("git rev-parse --abbrev-ref HEAD")