Add support for Bitwuzla SMT solver

[dguido]

Summary

Boolector has been archived and is no longer maintained. It has been succeeded by Bitwuzla, which is actively developed and provides improved performance and features.

Motivation

• Boolector is no longer maintained (final release was 3.2.4)
• Building Boolector from source in CI takes significant time (~2-3 minutes per job)
• Bitwuzla is the official successor with active development
• Bitwuzla provides prebuilt binaries, making CI installation much faster

Proposed Changes

1. Add Bitwuzla as a supported solver option in manticore/core/smtlib/solver.py
2. Add configuration options for Bitwuzla binary path
3. Update documentation to mention Bitwuzla as an alternative to Boolector
4. Consider deprecating Boolector support in a future release

Implementation Notes

• Bitwuzla supports the same SMT-LIB2 interface as Boolector
• Prebuilt binaries are available from: https://github.com/bitwuzla/bitwuzla/releases
• The solver integration should be similar to the existing Boolector implementation

References

• Bitwuzla repository: https://github.com/bitwuzla/bitwuzla
• Boolector deprecation notice: https://github.com/Boolector/boolector