New discovery code in solid-logic according to new WebID spec

[timea-solid]

After the discoveryLogic was introduced I noticed we have duplicate function names and duplicate code.
An overview:

TODO:

• move functions related to typeIndex from discoveryLogic to typeIndexLogic or decide what is better

• decide which functions should be exposed through SolidLogic object itself.

• propagate refactoring in rest of SolidOS stack.

[timbl]

In the new discovery code, we should use the process-wide store rather than having passed to each function.
So in fact to have

export async function loadPreferences (user: NamedNode)

instead of

export async function loadPreferences (store: LiveStore, user: NamedNode)

and so on. This is large change, but it is a simplifying change, so if we are refactoring let's do it.

[timea-solid]

Solid-logic PR: #44