Chore/39/replace rols dependency (#40)

• remove deprecated stato classes

these were deprecated several releases ago and are no longer used

• remove rols

replace with internal implementation

• fix for when ontology is zero length

• add .onload

sets ontology online option to true/false and detects correct state when loading the package

• add ontology method for model_seq

returns ontology for all models as well as the model sequence itself as a nested list

• fix typo in documentation

• rename ontology_set_online()

shortened to ontology_online()

• update vignette…

…to reflect changes to ontology interface

• Update README.rst

• import jsonlite

• fix .onload

defer the message to .onattach as per guidance

• import URLencode

• add documentation…

…for ontology(M) where M is a model sequence

• fix terms documentation for ontology_list

• remove stato generics

• fix tests for ontology_online

• import httr2

• fix BiocCheck warnings

• Use of “Error” in error message
• Use of class(m)[1]== in iterators
• Use of paste0 in stop()
• Escape curly brackets in roxygen blocks

• update news and version bump