feat(jans-auth-server): improve session lifetime properties

[yuriyz]

Description

Mike: The properties for sessionLifetime are a little confusing.
I wish we had one property for "cookie lifetime"
and one for "session lifetime" (i.e. the database entity)
the current names and corresponding defintions of the properties are very confusing.

YuriyZ: Idea was that we have sessionIdLifetime which sets session lifetime in both cookie and server object, so it's same (in sync) and with serverSessionIdLifetime we overwrite server object lifetime when needed. But yeah, confusion comes because we don't have dedicated property for each case, e.g.

• cookie case - sessionIdCookieLifetime
• server object case - sessionIdLifetime
  I can rename and change behavior accordingly

Mike: I think it would help a lot
We can just set the defaults the same...
sessionIdLifetime should = sessionIdCookieLifetime

Test cases and code coverage

• Write unit test to cover added/changed code
• Update integration tests to cover added/changed code

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Document the changes

• task for updating user guides if needed
• task for updating installation and configuration guides if needed
• task for updating developer documentation if needed
• task for updating technical documentation if needed