Merge 1.0.0a2

[dbdimitrov]

• Interactions names in tileplot and dotplot will now be sorted according to orderby when used; related to Sort interactions names in li.pl.tileplot by the orderby argument  #55

• Added filter_view_markers function to filter view markers considered background in MOFAcellular tutorial

• Added keep_stats parameter to adata_to_views to enable pseudobulk stats to be kept.

• Replace intra_groupby and extra_groupby with maskby in misty.
  The spots will now only be filtered according to maskby, such that both intra and extra both contain the same spots.
  The extra views are multiplied by the spatial connectivities prior to masking and the model being fit

• Merge MOFAcell improvements; related to keep psbulk stats when converting to MuData #42 and added remove_hvg_marker_genes function #29

• Targets with zero variance will no longer be modeled by misty.

• Resolve Clean up MISTy's pipeline #46 - refactored misty's pipeline

• Resolved logging and package import verbosity issues related to Verbosity/Logging #43

• Iternal .obs['label'] placeholder renamed to the less generic .obs['@Label']; related to Missing Resources #53

• Minor Readme & tutorial text improvements.