[ET-VK] Using a single GPU buffer for all tensor uniforms.

Pull Request resolved: https://github.com/pytorch/executorch/pull/7015

This diff changes Tensor class to store all uniforms in a single uniform buffer.

Entities stored in uniforms ie. size, stride, numel and logical limits are now stored in a single buffer and their offsets are stored as unsigned ints in Tensor class.

Other changes includes:
Adding a new ctor for ParamsBuffer class to allow allocation with size without data ptr.

Adding an offset input to Buffer::data function.

Adding an offset parameter to BufferBindInfo ctor, so additional offset can be supplied when binding a buffer.
ghstack-source-id: 256728325
@exported-using-ghexport

Differential Revision: [D65841750](https://our.internmc.facebook.com/intern/diff/D65841750/)

Co-authored-by: Vivek Trivedi <5340687+trivedivivek@users.noreply.github.com>