[Holidays plugin] Port partially to QQC2 and modernize UI

Summary:
- Port mostly to QQC2 (Don't touch the TableView since there's no QQC2 version yet)
- Use standard import names
- Adjust search field placeholder text to follow the common style

Test Plan: {F6821868}

Reviewers: #vdg, #plasma, ndavis

Reviewed By: #vdg, ndavis

Subscribers: ndavis, plasma-devel

Tags: #plasma

Maniphest Tasks: T10586

Differential Revision: https://phabricator.kde.org/D21194

plasmacalendarintegration/HolidaysConfig.qml

@@ -19,9 +19,10 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>
  */
 
-import QtQuick 2.0
-import QtQuick.Controls 1.2 as QtControls
-import QtQuick.Layouts 1.0
+import QtQuick 2.5
+import QtQuick.Controls 1.4 as QQC1
+import QtQuick.Controls 2.5 as QQC2
+import QtQuick.Layouts 1.3
 import QtQuick.Dialogs 1.1
 
 import org.kde.plasma.core 2.1 as PlasmaCore
@@ -29,10 +30,10 @@ import org.kde.plasma.components 2.0 as PlasmaComponents
 import org.kde.kholidays 1.0 as KHolidays
 import org.kde.holidayeventshelperplugin 1.0
 
-Item {
+ColumnLayout {
     id: holidaysConfig
-    width: parent.width
-    height: parent.height
+    anchors.left: parent.left
+    anchors.right: parent.right
 
     signal configurationChanged
 
@@ -42,7 +43,7 @@ Item {
     }
 
     // This is just for getting the column width
-    QtControls.CheckBox {
+    QQC2.CheckBox {
         id: checkbox
         visible: false
     }
@@ -51,16 +52,14 @@ Item {
         id: configHelper
     }
 
-    ColumnLayout {
-        anchors.fill: parent
-
-        QtControls.TextField {
+    QQC2.TextField {
         id: filter
         Layout.fillWidth: true
-            placeholderText: i18nd("kholidays_calendar_plugin", "Search Holiday Regions")
+        placeholderText: i18nd("kholidays_calendar_plugin", "Search...")
     }
 
-        QtControls.TableView {
+    // Still QQC1 bevcause there's no QQC2 TableView
+    QQC1.TableView {
         id: holidaysView
 
         signal toggleCurrent
@@ -80,9 +79,9 @@ Item {
             filterRole: "name"
         }
 
-            QtControls.TableViewColumn {
+        QQC1.TableViewColumn {
             width: checkbox.width
-                delegate: QtControls.CheckBox {
+            delegate: QQC2.CheckBox {
                 id: checkBox
                 anchors.centerIn: parent
                 checked: model ? configHelper.selectedRegions.indexOf(model.region) !== -1 : false
@@ -101,18 +100,17 @@ Item {
             resizable: false
             movable: false
         }
-            QtControls.TableViewColumn {
+        QQC1.TableViewColumn {
             role: "region"
             title: i18nd("kholidays_calendar_plugin", "Region")
         }
-            QtControls.TableViewColumn {
+        QQC1.TableViewColumn {
             role: "name"
             title: i18nd("kholidays_calendar_plugin", "Name")
         }
-            QtControls.TableViewColumn {
+        QQC1.TableViewColumn {
             role: "description"
             title: i18nd("kholidays_calendar_plugin", "Description")
         }
     }
-    }
 }