chore: unify sapi module getFeatures methods

chore: abstractify annotation service
bugfix: sapi region -> getFeatures now includes spatial feat
bugfix:  ieeg now sort by dataset
chore: udpate sapi schema
chore: move splashscreen to sapiviews/core/atlas
feat: added ieeg rich dataset support
chore: abstractify tree control
bugfix: race condition in encoding state in url
chore: added hooks when atlas/tmpl/parc changes
chore: remove unused var/methods
chore: updated get sapi schema script