Generate pseudo events

[noemifrisina]

Add the pseudo events generator that should still live in dials_research.

At this moment there is only an option to write event datasets full of zeros, implemented in order to generate example files for GDA. It would be good to have an actual fake event generator, which already exists and only needs some tidying up.

[noemifrisina]

While still pretty slow, the pseudo event generator is now working slightly better than before.
Aside from speed, the biggest issue right now is that the timestamps are exactly the same each chunk that gets written (so if eg. 3 chunks there will be the same (position, timestamp) repeated 3 times in the dataset)

[noemifrisina]

Log of event generation for one chunk of events for a Tristan2M detector:

2022-02-25 15:06:57,656 NeXusGenerator.writer.data INFO Start generating one chunk of pseudo events for (1, 2) modules of Tristan 2M
2022-02-25 15:08:14,632 NeXusGenerator.writer.data INFO Time taken to generate pseudo-event list: 76.91 s.

[noemifrisina]

Log of event generation for one chunk of events for a Tristan10M detector:

2022-02-25 16:39:13,304 NeXusGenerator.writer.data INFO Start generating one chunk of pseudo events for (2, 5) modules of Tristan 10M
2022-02-25 16:45:16,805 NeXusGenerator.writer.data INFO Time taken to generate pseudo-event list: 362.60 s.

Average time to then write events to each file: 0.40s.

[noemifrisina]

This will still need some improvement work ...