IB/uverbs: Move to new headers and make naming consistent

Use macros to make names consistent in ioctl() uAPI:
The ioctl() uAPI works with object-method hierarchy. The method part
also states which handler should be executed when this method is called
from user-space. Therefore, we need to tie method, method's id, method's
handler and the object owning this method together.
Previously, this was done through explicit developer chosen names.
This makes grepping the code harder. Changing the method's name,
method's handler and object's name to be automatically generated based
on the ids.

The headers are split in a way so they be included and used by
user-space. One header strictly contains structures that are used
directly by user-space applications, where another header is used for
internal library (i.e. libibverbs) to form the ioctl() commands.
Other header simply contains the required general command structure.

Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>