[doc] update docs, bump to version 1.3.0

[chore] update frontend dependencies version; update fastapi version to 0.109.2; pin onnxruntime version to 1.16.3; bump samgis version to 1.2.1

[refactor] move core instance segmentation (segment anything) functionality to samgis_core, bump to version 1.2.0

[refactor] renamed backend package to samgis

[docs] add first working sphinx docs build