Release v0.2.6dev

Epic 2 milestone #6 release version.

• Addition of custom NCS Pathway datasets, enabling creating, editing or removing of NCS pathways. - #211
• Implementation for custom priority weighting layers and their respective management
  (including adding, editing and removing layers) - #205
• New features regression fixes, including models layers usage- #209, #210
• Analysis area of interest updates - #220
• Coefficients and weighting setting - #226
• Fix in the processing engine when selecting priority layers for weighting implementation models - #218