LibSQL+SQLServer: Implement first cut of SELECT ... ORDER BY foo

Ordering is done by replacing the straight Vector holding the query
result in the SQLResult object with a dedicated Vector subclass that
inserts result rows according to their sort key using a binary search.
This is done in the ResultSet class.

There are limitations:
- "SELECT ... ORDER BY 1" (or 2 or 3 etc) is supposed to sort by the
n-th result column. This doesn't work yet
- "SELECT ... column-expression alias ... ORDER BY alias" is supposed to
sort by the column with the given alias. This doesn't work yet

What does work however is something like
```SELECT foo FROM bar SORT BY quux```
i.e. sorted by a column not in the result set. Once functions are
supported it should be possible to sort by random functions.

Userland/Libraries/LibSQL/ResultSet.cpp

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2022, Jan de Visser <jan@de-visser.net>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibSQL/ResultSet.h>
+
+namespace SQL {
+
+size_t ResultSet::binary_search(Tuple const& sort_key, size_t low, size_t high)
+{
+    if (high <= low) {
+        auto compare = sort_key.compare(at(low).sort_key);
+        return (compare > 0) ? low + 1 : low;
+    }
+
+    auto mid = (low + high) / 2;
+    auto compare = sort_key.compare(at(mid).sort_key);
+    if (compare == 0)
+        return mid + 1;
+
+    if (compare > 0)
+        return binary_search(sort_key, mid + 1, high);
+    return binary_search(sort_key, low, mid);
+}
+
+void ResultSet::insert_row(Tuple const& row, Tuple const& sort_key)
+{
+    if ((sort_key.size() == 0) || is_empty()) {
+        empend(row, sort_key);
+        return;
+    }
+    auto ix = binary_search(sort_key, 0, size() - 1);
+    insert(ix, ResultRow { row, sort_key });
+}
+
+}