Core: standardize the use of Clock

Upstream https://github.com/eclipse-dataspaceconnector/DataSpaceConnector/issues/1364

Standardize the use of Clock in the codebase, rather than constructs like Instant.now() which cannot be mocked easily. The Clock could be provided centrally.

Acceptance criteria

[x] No use of new Date(), Instant.now() or similar in runtime code.
[x] Single instance of Clock in shared context, also used for mocking.
[ ] ADR

Tasks

[x] Create Single instance of Clock in shared context
[x] Replace use of new Date(), Instant.now() or similar in runtime code, with shared Clock

agera-edc / DataSpaceConnector

Core: standardize the use of Clock #284

Acceptance criteria

Tasks