Documentation update

[dkazanc]

Checklist of things to complete the documentation update:

• [x] Introduction (all related subsections)
• [x] Templates generator
• [x] Process Lists Guide
• [x] YAML Checker
• [x] HTTomo Features
• [x] HTTomo Loaders
• [x] Full YAML pipelines
• [x] https://github.com/DiamondLightSource/httomo/issues/280 I added this subsection called Detailed concepts. May be there could be a good place to add some stuff on that.
• [x] #286
• [x] Add few basics steps on "How to Contribute" in Developers section
• [x] Add brief info on "How to interpret logger"
• [x] HTTomolibGPU documentation and links to correct functions in HTTomo

[dkazanc]

Completed Process Lists Guide. @yousefmoazzam could you please have a look, especially the side output part. If anything does not feel right, grammar or technical. thanks

[dkazanc]

@yousefmoazzam I've added a section on how to Interpret Log File. However, as for our discussion block/s VS s/block we probably need to modify it slightly when it becomes clearer?

[yousefmoazzam]

@dkazanc Nice, thanks for the explanations of the logfile contents, that's going to be quite useful to reference to people when the release comes!

Agreed, once we figure out the meaning/reason behind seeing block/s or s/block we should update that section accordingly.