Refactor UI and remove unused tests

- Deleted the generated UI file `untitled_ui.py` as it is no longer needed.
- Updated `search_statistic_page.ui` to enhance table properties, including grid style and sort indicators.
- Modified `search_statistic_page_ui.py` to reflect changes in the UI file and improve table header settings.
- Improved cleanup logic in `richtext.py` to ensure files are only deleted if they exist.
- Adjusted spacing in document generation for better formatting.
- Removed obsolete test files: `database_test.py`, `many_webrequest_test.py`, `test_database.py`, and `webrequest_test.py` to clean up the test suite.

src/ui/widgets/widget_sources/search_statistic_page_ui.py

@@ -1,6 +1,6 @@
 # Form implementation generated from reading ui file 'c:\Users\aky547\GitHub\SemesterapparatsManager\src\ui\widgets\widget_sources\search_statistic_page.ui'
 #
-# Created by: PyQt6 UI code generator 6.8.0
+# Created by: PyQt6 UI code generator 6.9.0
 #
 # WARNING: Any manual changes made to this file will be lost when pyuic6 is
 # run again.  Do not edit this file unless you know what you are doing.
@@ -175,6 +175,7 @@ class Ui_Dialog(object):
         self.tableWidget.setFocusPolicy(QtCore.Qt.FocusPolicy.NoFocus)
         self.tableWidget.setContextMenuPolicy(QtCore.Qt.ContextMenuPolicy.CustomContextMenu)
         self.tableWidget.setEditTriggers(QtWidgets.QAbstractItemView.EditTrigger.NoEditTriggers)
+        self.tableWidget.setGridStyle(QtCore.Qt.PenStyle.NoPen)
         self.tableWidget.setObjectName("tableWidget")
         self.tableWidget.setColumnCount(5)
         self.tableWidget.setRowCount(0)
@@ -189,6 +190,7 @@ class Ui_Dialog(object):
         item = QtWidgets.QTableWidgetItem()
         self.tableWidget.setHorizontalHeaderItem(4, item)
         self.tableWidget.horizontalHeader().setStretchLastSection(True)
+        self.tableWidget.verticalHeader().setSortIndicatorShown(True)
         self.verticalLayout_4.addWidget(self.tableWidget)
         self.verticalLayout_6.addLayout(self.verticalLayout_4)
         self.horizontalLayout.addWidget(self.app_results)
@@ -264,7 +266,9 @@ class Ui_Dialog(object):
         self.book_search_result.horizontalHeader().setCascadingSectionResizes(True)
         self.book_search_result.horizontalHeader().setDefaultSectionSize(200)
         self.book_search_result.horizontalHeader().setMinimumSectionSize(100)
+        self.book_search_result.horizontalHeader().setSortIndicatorShown(True)
         self.book_search_result.horizontalHeader().setStretchLastSection(True)
+        self.book_search_result.verticalHeader().setSortIndicatorShown(False)
         self.verticalLayout_2.addWidget(self.book_search_result)
         self.stackedWidget_4.addWidget(self.bookresult)
         self.verticalLayout_3.addWidget(self.stackedWidget_4)