More scalable entry logs view

Entry Log Viewer shows 50 elements. Experimental data, like the example ARPES data produces 155 elements. It would be good to

• select log levels (INFO, WARNING, ERROR, CRITICAL) using checkboxes
• select keys from the log entries, so the corresponding messages can be also displayed without the need of expanding each log entry one by one.
  Hence when checkbox for 'nexusparser' messages is selected, instead of
  INFO: Parsing (parsers/nexus)
  it would display
  INFO: Parsing (parsers/nexus) /entry/data/delays@units NXarpes:NXarpes.ENTRY.DATA.VARIABLE.units - fs