Deprecate ValueTransformer as it exposes masterFunction and variables properties

### Use case

Currently, `ReplaceStringWithFunctions` is hard to use, and it is hard to understand.
The class requires `masterFunction` and `variables`, however, it does not really use the variables.

### Possible solution

`ReplaceStringWithFunctions` was public for a long time already, and somebody might even created a subclass or passed a custom `CompoundVariable`, so I suggest deprecate all the old classes implementing `ValueTransformer` and add a new interface `ValueTransformer2` that will have just the transformation method.

### Possible workarounds

_No response_

### JMeter Version

5.5

### Java Version

_No response_

### OS Version

_No response_