Data types chapter desing

[PetroBondar]

Currently, the "Data types" chapter looks like this:

The proposed structure looks like this:

• Data types
  • Scalar data types (4.14.1. Scalar data types)
  • Vector data types (4.14.2. Vector types)
  • Math array types (4.14.3. Math array types)

PR with updates will be created soon. Feel free to comment if you have any suggestions on the structure.

[PetroBondar]

Created PR: https://github.com/KhronosGroup/SYCL_Reference/pull/119