resolves #190: add historyMaxAge parameter

[Fabilin]

Resolves #190 by introducing a mechanism to clean up local storage data for TOCK message history and quick replies based on a configurable historyMaxAge. If the age of the last message exceeds the defined maximum age, the relevant local storage keys are removed to ensure outdated data is not retained.

The historyMaxAge property is based on the tock_web_cookie_auth_max_age property configurable in the backend and is intended to be set to the same value.

[kbvi]

I might have put the + of lastMessageTime in its definition rather than its use (so something like +(windows... ?? 0) ), in case we need to use it later, as a uniquely typed variable...
But it's ok