puu-installer 1.0.53

- build: replace Meson build system with CMake (Jarkko Sakkinen)
- src: explicitly convert std::string_view to absl::string_view (Jarkko Sakkinen)
- engine: prioritize manifest target image reference in LoadTargetImgRef (Jarkko Sakkinen)
- engine: drop redundant MinTargetSizeBytes and WhichExists helpers (Jarkko Sakkinen)
- engine: avoid const_cast when wiping keys in secureboot (Jarkko Sakkinen)
- selfcheck: suppress bugprone-suspicious-include clang-tidy warnings (Jarkko Sakkinen)
- config: fix ValidatedString equality operator (Jarkko Sakkinen)

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@opinsys.fi>