[TASK] Update for vhs 2.0 compatibility

Current development branch of vhs is already with variable and namespaces.

CLI to update existing local stuff:
```bash
find ./ -type f -exec sed -i 's/=Tx_Vhs_ViewHelpers}/=FluidTYPO3\\Vhs\\ViewHelpers}/' {} \;
find ./ -type f -exec sed -i 's/v:var\./v:variable./' {} \; #Maybe you need multiple runs, if you use var. multiple times in a line
find ./ -type f -exec sed -i 's/v:if\./v:condition./' {} \; 
```