hal/hal_utils/dispatch_table.*: add another way to init descriptor

Now, we can initialize the exported function descriptor by means
of a different structure. This is necessary to keep function
description and function pointers separate (next commits).

This starts to solve github issue #48.
hal/sm_io/sm_io.*: add wrappers for new dispatch table function

This is just for convenience of the SMIO environment.
hal/sm_io/modules/acq/*: separate exported function descriptors

Step number 1 on fixing github issue #48
hal/sm_io/modules/dsp/*: separate exported function descriptors

Step number 2 on fixing github issue #48
hal/sm_io/modules/fmc130m_4ch/*: separate exported function descriptors

Step number 3 on fixing github issue #48
hal/sm_io/modules/swap/*: separate exported function descriptors

Final step on fixing #38 github issue