Improved parsed banking transaction mails/parsed mail logs.

- Added ability to change parsed mail's state.
- Added ability to change parsed mail's note.
- Added ability to track source bank account (updated `CsobMailParser` & `TatraBankaMailParser` + logging through `MailProcessor`)
- Refactored `ParsedMailLog`'s State constants/enum
- Added `EnumHelper` to simplify work with enum especially with Nette forms (enum values listing)

remp/respekt#189

src/Helpers/EnumHelper.php

@@ -0,0 +1,37 @@
+<?php
+
+namespace Crm\ApplicationModule\Helpers;
+
+/**
+ * @method static array cases() IDE helper because there can't be defined self::cases() as an abstract static method.
+ */
+trait EnumHelper
+{
+    public static function names(): array
+    {
+        return array_column(self::cases(), 'name');
+    }
+
+    public static function values(): array
+    {
+        return array_column(self::cases(), 'value');
+    }
+
+    /**
+     * List of enum values as 'enum value'=>'friendly name'. Initially intended for use in a Nette forms.
+     * Without overriding the method returns the 'friendly name' the same as the 'enum value' or
+     * in case of non-backed enum it returns a pair of 'enum keys'.
+     */
+    public static function getFriendlyList(): array
+    {
+        $values = self::values();
+
+        $isNonBackedEnum = count($values) === 0;
+        if ($isNonBackedEnum) {
+            $names = self::names();
+            return array_combine($names, $names);
+        }
+
+        return array_combine($values, $values);
+    }
+}