graphics/libertiff: Add libertiff 0.0.0.20250111

Libertiff is a C++11 simple, header-only, TIFF reader. It is MIT licensed.

Handles both ClassicTIFF and BigTIFF, little-endian or big-endian ordered.

The library does not offer codec facilities (and probably won't). It is mostly
aimed at browsing through the linked chain of Image File Directory (IFD) and
their tags.

"Offline" tag values are not loaded at IFD opening time, but only upon request,
which helps handling files with tags with an arbitrarily large number of values.

The library is thread-safe (that is the instances that it returns can be used
from multiple threads), if passed FileReader instances are themselves
thread-safe.

The library does not throw exceptions (but underlying std library might throw
exceptions in case of out-of-memory situations)

Optional features:

• define LIBERTIFF_C_FILE_READER before including libertiff.hpp, so that the libertiff::CFileReader class is available