Make startup checks configurable

This ticket was created from needs discovered in CASSANDRA-17180. We want to be able to configure a startup check so we figured out that it is necessary to treat all startup checks same - to be able to configure them. This ticket is about making startup checks configurable.

Once this ticket is done, we can continue with the implementation of CASSANDRA-17180 where the implementation of gc grace check will be done.

We have identified that there is one check currently in place which needs to be changed to reflect this configuration implementation and that is FileSystemOwnershipCheck.

Because startup checks were not configurable before via means of a configuration file, they were configurable via system properties. This ticket does not aim to get rid system properties configuration mechanism, system properties will have precedence over settings in configuration file. Then, in the next release, I am aiming to get rid of system properties configuration mechanism.