Material: Compatibility with older FCMat files

Provides compatibility loading older files outside the context of
a library.

Older material files were loaded by specifying a path. The new
material system used the path to associated the material with a
library, which may not be appropriate for legacy files. This change
allows the use of materials outside of a library.

Additionally, legacy files often have name/value pairs not part of the
standard list of properties. Since these were unable to be mapped to
a model property they were ignored. Materials now maintain a legacy
map to hold properties not associated with a property model. These
properties are considered transient and will not be saved. It is not
intended for this feature to be used as a generic container for
properties not mapped to an appropriate model.

Fixes #13302

src/Mod/Material/App/Materials.cpp

@@ -499,6 +499,9 @@ Material::Material(const Material& other)
         MaterialProperty prop(it.second);
         _appearance[it.first] = std::make_shared<MaterialProperty>(prop);
     }
+    for (auto& it : other._legacy) {
+        _legacy[it.first] = it.second;
+    }
 }
 
 QString Material::getAuthorAndLicense() const
@@ -890,6 +893,13 @@ void Material::setAppearanceValue(const QString& name,
     }
 }
 
+void Material::setLegacyValue(const QString& name, const QString& value)
+{
+    setEditStateAlter();
+
+    _legacy[name] = value;
+}
+
 std::shared_ptr<MaterialProperty> Material::getPhysicalProperty(const QString& name)
 {
     try {
@@ -1047,6 +1057,19 @@ bool Material::hasAppearanceProperty(const QString& name) const
     return true;
 }
 
+bool Material::hasNonLegacyProperty(const QString& name) const
+{
+    if (hasPhysicalProperty(name) || hasAppearanceProperty(name)) {
+        return true;
+    }
+    return false;
+}
+
+bool Material::hasLegacyProperties() const
+{
+    return !_legacy.empty();
+}
+
 bool Material::isInherited(const QString& uuid) const
 {
     if (_physicalUuids.contains(uuid)) {
@@ -1464,6 +1487,10 @@ Material& Material::operator=(const Material& other)
         MaterialProperty prop(it.second);
         _appearance[it.first] = std::make_shared<MaterialProperty>(prop);
     }
+    _legacy.clear();
+    for (auto& it : other._legacy) {
+        _legacy[it.first] = it.second;
+    }
 
     return *this;
 }