Inefficiencies in symmeterize_sqw related to filebacked operations

[abuts]

Current summeterize_sqw algorithm used apply for performing symmetry transformation. This is not a good choice, as symmetry operation moves pixels from its image bins.

To avoid this, all pixels are collated into single bin and this bin is later cut/rebinned into final symmeterized object.

If input data are filebacked data, this would lead to at least two read/write operations over whoule pixel file until the result is achieved.

As symmetry operation is a projection type operation, the symmeterize_sqw should be better implemented through projections, which would allow single path through the whole operation.

Other issue is hash deprecation of old symmeterize_sqw interface. People are widely use it, so it is not diffcult to create new symmetry operation internaly and issue deprecation warning rather then throwing deprecation error.

CM:28.11.23
Low priority