[TASK] Standardise the spelling of ViewHelpers to lowerCamelCase

It is common practice to write ViewHelpers in Fluid templates in
lowerCamelCase.
Adherence to this standard also supports code completion in IDEs,
for example.

Author: julianhofmann

Resources/Private/Partials/Form/Page.html

@@ -6,7 +6,7 @@
 
     <f:for each="{page.fields}" as="field" iteration="iteration">
         <vh:misc.createRowTags columns="{settings.styles.numberOfColumns}" class="{settings.styles.framework.rowClasses}" iteration="{iteration}">
-            <f:render partial="Form/Field/{vh:String.Upper(string:field.type)}" arguments="{field:field}"/>
+            <f:render partial="Form/Field/{vh:string.upper(string:field.type)}" arguments="{field:field}"/>
         </vh:misc.createRowTags>
     </f:for>
 

Resources/Private/Templates/Form/PowermailAll.html

@@ -37,10 +37,10 @@
 <f:section name="mail">
 	<table class="powermail_all">
 		<f:for each="{mail.answers}" as="answer">
-			<f:if condition="{vh:Condition.isNotExcludedFromPowermailAll(answer:answer, type:type, settings:settings)}">
+			<f:if condition="{vh:condition.isNotExcludedFromPowermailAll(answer:answer, type:type, settings:settings)}">
 				<f:if condition="{settings.misc.showOnlyFilledValues}">
 					<f:then>
-						<f:if condition="{vh:Condition.IsNotEmpty(val:'{answer.value}')}">
+						<f:if condition="{vh:condition.isNotEmpty(val:'{answer.value}')}">
 							<f:render partial="PowermailAll/Mail" arguments="{_all}" />
 						</f:if>
 					</f:then>

Resources/Private/Templates/Module/ExportXls.html

@@ -18,7 +18,7 @@
 							<th>
 								<f:if condition="{vh:condition.isNumber(val:fieldUid)}">
 									<f:then>
-										<vh:Getter.GetFieldLabelFromUid uid="{fieldUid}" />
+										<vh:getter.getFieldLabelFromUid uid="{fieldUid}" />
 									</f:then>
 									<f:else>
 										<f:translate key="\In2code\Powermail\Domain\Model\Mail.{vh:string.underscoredToLowerCamelCase(val:fieldUid)}" extensionName="powermail" />
@@ -65,7 +65,7 @@
 															<f:format.date format="%M:%S"><vh:misc.variableInVariable obj="{mail}" prop="{fieldUid}" /></f:format.date>
 														</f:then>
 														<f:else>
-															<f:format.date format="H:i:s"><vh:Misc.VariableInVariable obj="{mail}" prop="{fieldUid}" /></f:format.date>
+															<f:format.date format="H:i:s"><vh:misc.variableInVariable obj="{mail}" prop="{fieldUid}" /></f:format.date>
 														</f:else>
 													</f:if>
 												</f:else>