Use pointers to pass state objects to service constructors
to work around GCC 12 warning
error: member ‘wsrep::mock_storage_service::client_state_’
is used uninitialized
Removed calls to assert() from public headers to have
full control when assertions are enabled in wsrep-lib
code regardless of parent project build configuration.
Moved methods containing assertions and non-trivial
code from headers into compilation units.
The intended purpose for local mode was local storage access without
entering replication hooks. However, the same can be achieved with
high priority mode. Removed replicating mode and use local instead to
denote locally processing clients.
