[license] Add should-be-expanded display option to license entries

- In code, add the necessary bool
 - document meaning in the config file
 - actually expand the full text if the entry is local and set to expanding-
   by-default. This implementation is a bit lazy since it just pretends
   to click on the toggle button.
 - While here, reduce scope for UB by initializing POD members

src/modules/license/LicensePage.cpp

@@ -72,6 +72,7 @@ LicenseEntry::LicenseEntry( const QVariantMap& conf )
     m_url = QUrl( conf[ "url" ].toString() );
 
     m_required = CalamaresUtils::getBool( conf, "required", false );
+    m_expand = CalamaresUtils::getBool( conf, "expand", false );
 
     bool ok = false;
     QString typeString = conf.value( "type", "software" ).toString();

src/modules/license/LicensePage.h

@@ -56,13 +56,15 @@ struct LicenseEntry
     bool isValid() const { return !m_id.isEmpty(); }
     bool isRequired() const { return m_required; }
     bool isLocal() const;
+    bool expandByDefault() const { return m_expand; }
 
     QString m_id;
     QString m_prettyName;
     QString m_prettyVendor;
-    Type m_type;
+    Type m_type = Type::Software;
     QUrl m_url;
-    bool m_required;
+    bool m_required = false;
+    bool m_expand = false;
 };
 
 class LicensePage : public QWidget

src/modules/license/LicenseWidget.cpp

@@ -98,6 +98,13 @@ LicenseWidget::LicenseWidget( LicenseEntry entry, QWidget* parent )
 
         vLayout->addWidget( m_fullText );
         setLayout( vLayout );
+
+        if ( m_entry.expandByDefault() )
+        {
+            // Since we started in a collapsed state, toggle it to expand.
+            // This can only be done once the full text has been added.
+            expandClicked();
+        }
     }
     else
     {

src/modules/license/license.conf

@@ -14,6 +14,10 @@
 #               to the URL is provided, which opens in the default web browser. A local
 #               URL (i.e. file:///) assumes that the contents are HTML or plain text, and
 #               displays the license in-line. YAML: string, mandatory.
+#   - expand    A boolean value only relevant for **local** URLs. If true,
+#               the license text is displayed in "expanded" form by
+#               default, rather than requiring the user to first open it up.
+#               YAML: boolean, optional, default is false.
 entries:
 - id:       nvidia
   name:     Nvidia
@@ -43,3 +47,4 @@ entries:
   type: software
   required: true
   url: file:../LICENSE
+  expand: true