[1/3] update openapi spec: update generator

Update the generator to be able to handle the new challenges that arose
with the new specification, namely:

- Enums that do not start with a capital letter
- Enums that contain a reserved keyword
- Basic handling 'allOf' keys in properties

Additionally, the comparison enum deserialisation is now
case-insensitive.

core/codegen/enum_implementation.hbs

@@ -13,9 +13,9 @@ template <>
 
 	QString str = source.toString();
 
-	{{#each values as |value|}}
-	if (str == QStringLiteral("{{value}}")) {
-		return {{className}}::{{value}};
+	{{#each entries as |entry|}}
+	if (str == QStringLiteral("{{entry.value}}")) {
+		return {{className}}::{{entry.name}};
 	}
 
 	{{/each}}
@@ -27,9 +27,9 @@ template <>
 QJsonValue toJsonValue(const {{className}} &source, convertType<{{className}}>) {
 	switch(source) {
 
-	{{#each values as |value|}}
-	case {{className}}::{{value}}:
-		return QStringLiteral("{{value}}");
+	{{#each entries as |entry|}}
+	case {{className}}::{{entry.name}}:
+		return QStringLiteral("{{entry.value}}");
 
 	{{/each}}