create merge clover coverage command

src/Clover/Dto/LineDto.php

@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Dannecron\CoverageMerger\Clover\Dto;
+
+class LineDto
+{
+    /**
+     * @param array<string, string> $properties Other properties on the line.
+     *                               E.g. name, visibility, complexity, crap
+     * @param int $count Number of hits on this line
+     */
+    public function __construct(
+        private array $properties,
+        private int $count,
+    ) {
+    }
+
+    public function getCount(): int
+    {
+        return $this->count;
+    }
+
+    public function getProperties(): array
+    {
+        return $this->properties;
+    }
+
+    public function getNum(): ?int
+    {
+        return isset($this->properties['num'])
+            ? (int) $this->properties['num']
+            : null;
+    }
+
+    public function merge(LineDto $otherLine): self
+    {
+        $this->properties = \array_merge($otherLine->getProperties(), $this->properties);
+        $this->count += $otherLine->getCount();
+
+        return $this;
+    }
+}