Refactoring of Instrument list and Parameters creation

[dsavchenko]

Refactoring in Instruments/Parameters creation. For optimisation and bug-fixing. This will really reduce the overhead and there will be no more gateway timeouts, I hope.

• Reduce the number of requests for the backend description.
• No need to reload the plugin to update the information from KG about available instruments (it gets updated before an iteration of the instrument factory "list").
• instr_name and instrument_query are attached as attributes to the instrument_factory. This allows to avoid the creation of every Instrument in each request.
• Fixed issue with changing default values, still keeping lru_cache for parameter lists.
• Fixed issue with "token" parameter name masking.
• Pass Ontology instance to Parameter.from_owl_uri in order to not recreate it.

NOTE: one breaking change is introduced. The default KG url is removed, as the info in kg is really deployment-specific.

[burnout87]

one question

[volodymyrss]

Ok, thanks. Though this performance-driven variation in factory may add some confusion. I could imagine other solutions, but it makes sense to do this for now.