Use time service in KeyValueDatabaseExpirableFactory and DatabaseStorageExpirable classes

Problem/Motivation

REQUEST_TIME constant is marked as deprecated and a time service was added to 8.3.x in #2717207: Add a time service to provide consistent interaction with time()/microtime() and superglobals → .
See parent issue 📌 [meta][no patch] Replace uses of REQUEST_TIME and time() with time service Active for full description.
Here is the change record → also.

Proposed resolution

All occurrence in code should be updated to remove deprecated uses of REQUEST_TIME, time() and microtime().

Remaining tasks

None

User interface changes

None

API changes

None

Data model changes

None