FastTrack code and slides update for ISC25

[bcosenza]

Updated source.cpp and solution.cpp for AsynchronousExecution:

• replaced auto with actual types
• added namespace sycl
• removed the two codes with USM

Added links to CompilerExplorer (CE) in README

• added two links for CE equivalent code for source.pp and solution.cpp
• the 2 codes have a quick check function that remove the need to have the helper function in another file, which does not seem to work properly in CE (at lesat, with SYCL)
• SYCL 2024.2.1

Slide update

• removed slides using convolution kernels
• added slide with CE reference