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

Remove quite useless `gitRevisionDate`.

libraries/core/src/main/kotlin/io/element/android/libraries/core/meta/BuildMeta.kt

@@ -25,7 +25,6 @@ data class BuildMeta(
     val versionName: String,
     val versionCode: Int,
     val gitRevision: String,
-    val gitRevisionDate: String,
     val gitBranchName: String,
     val flavorDescription: String,
     val flavorShortDescription: String,

libraries/matrix/test/src/main/kotlin/io/element/android/libraries/matrix/test/core/BuildMeta.kt

@@ -28,7 +28,6 @@ fun aBuildMeta(
     versionName: String = "",
     versionCode: Int = 0,
     gitRevision: String = "",
-    gitRevisionDate: String = "",
     gitBranchName: String = "",
     flavorDescription: String = "",
     flavorShortDescription: String = "",
@@ -41,7 +40,6 @@ fun aBuildMeta(
     versionName,
     versionCode,
     gitRevision,
-    gitRevisionDate,
     gitBranchName,
     flavorDescription,
     flavorShortDescription