Initial experiments using the new Database query logic with Conditional Statistical Functions (#1880)

- Refactoring of the Statistical Conditional functions (`AVERAGEIF()`, `AVERAGEIFS()`, `COUNTIF()`, `COUNTIFS()`, `MAXIFS()` and `MINIFS()` to use the new Database functions codebase.
- Extended unit testing
- Fix handling for null values
- Fixes to wildcard text searches

There's still scope for further improvements to memory usage and performance; but for now the code is stable with all unit tests passing

tests/data/Calculation/Statistical/MINIFS.php

@@ -21,6 +21,20 @@ return [
         ],
         '=H',
     ],
+    [
+        1,
+        [
+            [1],
+            [2],
+            [3],
+        ],
+        [
+            ['Y'],
+            ['Y'],
+            ['N'],
+        ],
+        '=Y',
+    ],
     [
         2,
         [
@@ -41,4 +55,18 @@ return [
         ],
         '=B',
     ],
+    [
+        125000,
+        [223000, 125000, 456000, 322000, 340000, 198000, 310000, 250000, 460000, 261000, 389000, 305000],
+        [1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4],
+        1,
+    ],
+    [
+        261000,
+        [223000, 125000, 456000, 322000, 340000, 198000, 310000, 250000, 460000, 261000, 389000, 305000],
+        [1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4],
+        '>2',
+        ['Jeff', 'Chris', 'Carol', 'Jeff', 'Chris', 'Carol', 'Jeff', 'Chris', 'Carol', 'Jeff', 'Chris', 'Carol'],
+        'Jeff',
+    ],
 ];