Fix SAT warnings (#14202)

* Fix SAT warnings

- checkstyle.ModifierOrderCheck
- checkstyle.OneStatementPerLineCheck
- checkstyle.NeedBracesCheck
- PMD.UseStandardCharsets
- PMD.UseCollectionIsEmpty
- PMD.UnusedLocalVariable
- PMD.SimplifyBooleanReturns where reasonable, suppress where
readability is better without change
- PMD.SimplifyBooleanExpressions

* Include StandardCharsets

Signed-off-by: Holger Friedrich <mail@holger-friedrich.de>

bundles/org.openhab.binding.tankerkoenig/src/main/java/org/openhab/binding/tankerkoenig/internal/handler/StationHandler.java

@@ -128,7 +128,7 @@ public class StationHandler extends BaseThingHandler {
      */
     public void updateData(LittleStation station) {
         logger.debug("Update Tankerkoenig data '{}'", getThing().getUID());
-        if (station.isOpen() == true) {
+        if (station.isOpen()) {
             logger.debug("Checked Station is open! '{}'", getThing().getUID());
             updateState(CHANNEL_STATION_OPEN, OpenClosedType.OPEN);
             if (station.getDiesel() != null) {