[Database] Add dependency to Platform service

Add a dependency (via declarative services) to
PersistenceProvider, upon Platform. This prevents
the PersistenceProvider from being instantiated
before the platform is available; this also
means that platform's activator may be started
before the database is started. This allows for
a database startup timer to start before getting
stuck in a long DB wait, which allows for user
feedback regarding nasa/mct#225.
[Platform] Start persistence timer earlier

Start the persistence timer before initializing
services and handlers. These services/handlers
include the Platform, the introduction of which
may trigger the dependent databasePersistence
to begin launching.

Since databasePersistence's instantiation time
may be long, it is necessary to start the
timer before that service.
[Platform] Split startup timer into intervals

Split database initialization timer up into
warning and error intervals, so allow user
notification needed in nasa/mct#225 without
forcing an early shutdown.
[Platform] Show dialog if persistence seems unavailable

Show a warning message if it is taking abnormally
long to obtain a persistence provider (for
instance, because the database connection is
unavailable or host is inaccessible.)
[Platform] Use hints when showing persistence warning

Use hints to employ the Platform window manager's
styling when showing a message to indicate that
persistence is taking too long to activate.
[Platform] Add license header to Activator
[Platform] Move persistence warnings to bundle
[Platform] Show dialog before second persistence failure

Show dialog before exiting after failing to
obtain persistence for a full minute.
[Platform] Adjust timing of persistence dialog

Wait longer (ten seconds instead of five) before
showing a warning that persistence is taking too
long to initialize. (This warning message is
associated with nasa/mct#225)

This extra duration should help minimize
instances where the user is shown the warning
when a database is actually available.
Merge pull request #226 from VWoeltjen/mct225

[Database] Show warning if persistence seems unavailable