Update SPI locking to match JCR 2.0

jcr2spi currently uses the JSR 170 way to determine whether a given Session owns the lock by checking of the lock token is null.
with JSR 283 a new Lock method has been defined for this, while on the other hand the lock token is always null for session-scoped
locks.

In addition 283-locking allows to specify a timeout hint and hint about the owner info that should be displayed
for information purpose.

Proposed changes to SPI:

• extend org.apache.jackrabbit.spi.LockInfo to cover the new functionality added with JSR 283
• add an variant of RepositoryService.lock that allows to specify timeout and owner hint.

Proposed changes to JCR2SPI:

• change jcr2spi to make use of the new functionality and modify the test for session being lock holder.
  this mainly affects
  > LockOperation
  > LockManager impl
  > Lock impl