N°2847 - Work on the ActivityPanel and PopoverMenu features

- Deprecate cmdbAbstractObject::DisplayBareHistory() as history will be replace by ActivityPanel
- Rename illustrations to original filenames to find source more easily
- Remove unused "max_history_case_log_entry_length" config. parameter
- Activity panel: Introduce iCMDBChangeOp and iCMDBChangeOpSetAttribute interface for better dependency injection
- Activity panel: Add placeholder when no entry
- Activity panel: Fix tab toolbar icons color
- Activity panel: Add history entries (entries after the first 50 are not loaded yet)
- Popover menu: Fix no border-radius on first/last entries hover

css/backoffice/layout/activity-panel/_transition-entry.scss

@@ -0,0 +1,27 @@
+/*!
+ * Copyright (C) 2013-2020 Combodo SARL
+ *
+ * This file is part of iTop.
+ *
+ * iTop is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * iTop is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ */
+
+/* SCSS variables */
+$ibo-transition-entry--original-state-label--text-color: $ibo-color-grey-800 !default;
+$ibo-transition-entry--original-state-label--text-decoration: line-through !default;
+
+/* Main information */
+.ibo-transition-entry--original-state-label{
+	color: $ibo-transition-entry--original-state-label--text-color;
+	text-decoration: $ibo-transition-entry--original-state-label--text-decoration;
+}