[LifetimeSafety] Make the dataflow analysis generic (#148222)

Refactored the lifetime safety analysis to use a generic dataflow framework with a policy-based design.

### Changes

- Introduced a generic `DataflowAnalysis` template class that can be specialized for different analyses
- Renamed `LifetimeLattice` to `LoanPropagationLattice` to better reflect its purpose
- Created a `LoanPropagationAnalysis` class that inherits from the generic framework
- Moved transfer functions from the standalone `Transferer` class into the analysis class
- Restructured the code to separate the dataflow engine from the specific analysis logic
- Updated debug output and test expectations to use the new class names

### Motivation

In order to add more analyses, e.g. [loan expiry](#148712) and origin liveness, the previous implementation would have separate, nearly identical dataflow runners for each analysis. This change creates a single, reusable component, which will make it much simpler to add subsequent analyses without repeating boilerplate code.


This is quite close to the existing dataflow framework!

Author: usx95