Make main tracking browser resizable by user

sohstationviewer/view/ui/main_ui.py

@@ -7,6 +7,7 @@ from PySide2.QtWidgets import (
     QMainWindow, QWidget, QTextBrowser, QPushButton, QLineEdit, QDateEdit,
     QListWidget, QCheckBox, QRadioButton, QMenu, QLabel, QFrame,
     QVBoxLayout, QHBoxLayout, QGridLayout, QAbstractItemView, QButtonGroup,
+    QSplitter,
 )
 from PySide2.QtWidgets import (
     QAction, QActionGroup, QShortcut
@@ -357,18 +358,18 @@ class UIMainWindow(object):
 
         self.set_control_column(left_layout)
 
-        plot_layout = QVBoxLayout()
-        h_layout.addLayout(plot_layout, 2)
+        plot_splitter = QSplitter(QtCore.Qt.Orientation.Vertical)
+        h_layout.addWidget(plot_splitter, 2)
 
         self.plotting_widget = SOHWidget(self.main_window,
                                          self.tracking_info_text_browser,
                                          'SOH',
                                          self.main_window)
-        plot_layout.addWidget(self.plotting_widget)
+        plot_splitter.addWidget(self.plotting_widget)
 
         self.tracking_info_text_browser.setMinimumHeight(60)
         self.tracking_info_text_browser.setMaximumHeight(80)
-        plot_layout.addWidget(self.tracking_info_text_browser)
+        plot_splitter.addWidget(self.tracking_info_text_browser)
 
     def set_control_column(self, left_layout):
         """