[libtapasco] Limit printing buffer contents in debug trace

[tsmk94]

When running software with RUST_LOG=trace the content of every buffer copied to/from device memory is printed byte-wise multiple times. Thus, the debug trace is quite useless as soon as buffer sizes get bit larger than some kilobytes.

In my oppinion it would be sufficient and make much more sense to only print the first couple elements (e.g. 100) bytes of the buffer to be copied to device memory.