Rename product files and add sdk splash

Both sloeber product and the sdk product were called arduino.products.
Which is on its own a bad name and confusing

Author: jan

io.sloeber.product.sdk/plugin.xml

@@ -0,0 +1,46 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<?eclipse version="3.4"?>
+<plugin>
+
+   <extension
+         id="product"
+         point="org.eclipse.core.runtime.products">
+      <product
+            name="Sloeber"
+            application="org.eclipse.ui.ide.workbench">
+         <property
+               name="windowImages"
+               value="icons/logo_16.png,icons/logo_32.png,icons/logo_48.png,icons/logo_64.png,icons/logo_128.png,icons/logo_256.png">
+         </property>
+         <property
+               name="aboutText"
+               value="Sloeber, the Eclipse IDE for Arduino Developers&#x0A;&#x0A;Info: https://eclipse.baeyens.it/&#x0A;Source: https://github.com/sloeber/arduino-eclipse-plugin&#x0A;&#x0A;&#x0A;Contributors (github users): jantje, wimjongman, rlogiacco, MarceloLimori, brodykenrick, neuweiler, darcade, amorellgarcia&#x0A;&#x0A;https://github.com/sloeber/arduino-eclipse-plugin/graphs/contributors">
+         </property>
+         <property
+               name="aboutImage"
+               value="icons/eclipse_lg.png">
+         </property>
+         <property
+               name="startupForegroundColor"
+               value="C8D5EA">
+         </property>
+         <property
+               name="startupProgressRect"
+               value="97,370,100,4">
+         </property>
+         <property
+               name="startupMessageRect"
+               value="400,370,441,20">
+         </property>
+         <property
+               name="appName"
+               value="Sloeber">
+         </property>
+         <property
+               name="preferenceCustomization"
+               value="plugin_customization.ini">
+         </property>
+      </product>
+   </extension>
+
+</plugin>

io.sloeber.product.sdk/arduino.product renamed to io.sloeber.product.sdk/sdk.product

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <?pde version="3.5"?>
 
-<product name="Sloeber" uid="io.sloeber.product" id="org.eclipse.sdk.ide" application="org.eclipse.ui.ide.workbench" version="4.4.2.qualifier" type="features" includeLaunchers="true" autoIncludeRequirements="false">
+<product name="Sloeber" uid="io.sloeber.product.sdk" id="io.sloeber.product.sdk.product" application="org.eclipse.ui.ide.workbench" version="4.4.2.qualifier" type="features" includeLaunchers="true" autoIncludeRequirements="false">
 
    <aboutInfo>
       <image path="/io.sloeber.product.sdk/icons/eclipse_lg.png"/>