Connect EditSingleParamDialog with ValueColorEdit

closes #194 (closed)

Beside connecting EditSingleParamDialog with ValueColorEdit, this MR has the following changes:

• Combine 'description' with 'instruction' in plot_type_info to remove redundancy.
• Add check in ValueColors string for number of valueColor, duplicated value, order of value
• Show error when checking ValueColors string the first time ValueColorEdit is created to help developer check if ValueColors that are added into DB not from the GUI are valid.

sohstationviewer/view/db_config/param_helper.py

+from typing import Tuple
+import re
+from sohstationviewer.view.util.plot_type_info import plot_types
+
+
+def validate_value_color_str(value_color_string: str,
+                             plot_type: str,
+                             row_id: int = 0) -> Tuple[bool, str]:
+    plot_type_info = plot_types.get(plot_type)
+
+    value_colors = value_color_string.split("|")
+    if 'total_value_color_required' in plot_type_info:
+        if len(value_colors) != plot_type_info['total_value_color_required']:
+            msg = (f"Row {row_id}: Total ValueColors in this row is "
+                   f"{len(value_colors)} while it requires "
+                   f"{plot_type_info['total_value_color_required']} for "
+                   f"plot type {plot_type}.")
+            return False, msg
+
+    values = []
+    numbers = []
+    for vc in value_colors:
+        vc = vc.strip()
+        if plot_type_info is None:
+            continue
+        if not plot_type_info['pattern'].match(vc):
+            msg = (f"Row {row_id}: A ValueColor in this row is "
+                   f"'{vc}', which doesn't match the required "
+                   f"format of\n\n"
+                   f"{plot_type_info['description']}")
+            return False, msg
+        val = vc.split(":")[0]
+        if val in values:
+            msg = f"Row {row_id}: Duplicated value '{val}' isn't allowed."
+            return False, msg
+        number = re.sub('<|=', '', val)
+        if numbers and number < max(numbers):
+            msg = (f"Row {row_id}: Number '{number}' is out of increasing "
+                   f"order.")
+            return False, msg
+        values.append(val)
+        numbers.append(number)
+
+    return True, ''