H2M: add software-based pattern generator for lab testing and change print output from h2m_pixels

This MR introduces two changes for the H2M device:

to facilitate lab testing, the triggerPatternGenerator function is implemented. It triggers the pattern generator and enables readout from the FIFO with the new addition to the config file:

force_read_from_fifo

Secondly, the print function in devices/H2M/h2m_pixels.hpp is modified to provide output which complies better with the acquire and scanThreshold methods in pearycli.

Previous output:

out << "px [";
      out << m_mode << "|" << m_data;
      out << "]";

New output:

out << static_cast<int>(m_mode) << "," << static_cast<int>(m_data);