Scope reduction (#41)

Renamed PensionStatementBasic to PensionStatement
Common sub-schema PersonalPensionDetails introduced for PensionStatement
and Policy
Outputs of the simulations have been aligned to use PensionStatements
Security changed to OAuth2 with scope read:basic_pension_data for all
endpoints
Sensitive components disabilityDegree and healthReservations removed
(Reason: Missing granularity in access control)
Purchase endpoints removed (Reason: Currently unused and not reviewed by
community)
Removed definition of Directory API & Consent API (Reason: They are not
yet production ready)

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Co-authored-by: Michael <[email protected]>