better names for `[GET] /workspace/ws_id/files`'s return type's properties.. `size` instead of `filesize` etc.

add info field to GetFileResponseData interface and display the the additional useful data it can contain

removed all code concerning workspace-monitor (feature not used anymore or unclear what benefit it is of)

As in verona-player-interface- 2.1.0 requested, the `playerConfig` in `vopReadyNotification` now

* includes `pagingMode`, `stateReportPolicy` and `logPolicy` from bookletConfig

* includes `unitNumber`, `unitTitle`, `unitId`

* it includes also `unitCount`, which is not part of the verona-2.1.0-interface, but proposed here: https://github.com/verona-interfaces/player/issues/24

fixes #221

rename TERMINATING to TERMINATED wo have the one reported to backend/monitor to be TERMINATED and teh internale state (former TERMINATED) wich cames when locking was successful to FINISHED (not LOCKED because possible future confusion)

why? because if I pause a (checked) session, and the state changes to PAUSED, the remaianing session in checkedSessions still is not PAUSED and the "Pause"-button stays active which would be wrong.. Although this could have led to other subtile bugs in the future.

endpoints for responses and restorepoints need timeStamp now, not timestamp to resemble the verona 2 standard

restore reporting of PAGES_COUNT and PAGE_NR which are needed by monitor; also fix some bugs about page-reporting