Migration to portal

[dcolleoni]

Rename :
IFRS17CalculationEngine
IFRS17Client

Create directories for files in the root:
DataStructure => move inside /DataModel/
=> remove identities and ReportVariable (check for others) and move them into Import and Reporting
Utils => /Utils/ => break the current Utils NB in its subsections

In the root there should be only:
Directories
Readme
OverviewCalculationEngine
InputFormatDescription