[optimizer] Cleanup optimizer and remove dependency on weight

[optimizer] Cleanup optimizer and remove dependency on weight

Cleanup optimizer interface where some extra interfaces have been
removed, and arguments interface has been updated.
Further, the dependency on weight header has been removed, and added an
optimizer context interface which provides an interface to weight
related tensors required by the optimizer.

Signed-off-by: Parichay Kapoor <pk.kapoor@samsung.com>