Sysdyn model browser context update

Sysdyn model browser context update

+ Re-introduce missing model browser contexts such as import, export,
new
for libraries, functions, charts and more for Sysdyn models. Full list:

Modules: Import Module
Experiments: New Game Experiment, New Sensitivity Analysis Experiment
Functions: Import Function Library
Function Library: Export Function Library, New Function, New Function
Library
Charts: New Sensitivity Chart
Experiment: Assign IC
Model: Export Model
History Dataset: Show in charts
Module: Assign Symbol Groups..., Export Module
Model: Open Diagram Editor (also works with double-click)

+ Reintroduced "Initial Conditions" folder under sysdyn model

+ Allow underscore characters in sysdyn name validator

+ Use SpreadsheetUtils and SpreadsheetGraphUtils (not sysdyn.SheetUtils)
to create new books and spreadsheets for Sysdyn models. This way the
implementation relies on the platform implementation and doesn't need to
copy-paste the implementation to a sysdyn-specific SheetUtils class.

+ Previously, deleting a Module only removed the Symbol associated with
it, leaving the Module itself intact and listed under the .sysdyn
model's graph. Now, a separate remover for deleting a module has been
added that checks if the deleted resource is a symbol, in which case it
searches for the parent Module and deletes that instead of the symbol.

+ Refactor testGraph to sub-folder

+ Make changes to various async and sync requests to take into account
changes in platform.

+ Replace all deprecated usage of SimanticsUI with Simantics

+ Fix PlaybackSliderContribution

+ ModelBrowser view shows type of Variables again (just like in 1.9.1).
I.e. NAME : TYPE (e.g MAX DISCOVERY RATE : Auxiliary).

gitlab #7
gitlab #3
gitlab #18
gitlab #13
gitlab #19
gitlab #20
gitlab #21
gitlab #23
gitlab #24
gitlab #25
gitlab #26
gitlab #27

closes #7
closes #3
closes #18
closes #13
closes #19
closes #20
closes #21
closes #23
closes #24
closes #25
closes #26
closes #27

Change-Id: I2e93cbd6497c77d4796c91e32f64f0d43749ba3c