Investigate use of fuser and group by funcs with new s2a

[vnewey]

We need to check our use of fuser functions is appropriate for when we include the new s2a data.
One option is to load s2a data separately to s2b and s2c, so that it isn't impacted by the group by solar_day that we use in io.py.

dea-intertidal/intertidal/io.py

Line 332 in 5960791

"group_by": "solar_day",

related issue:
#154