Gaps in Device Management

[PokhodenkoSA]

Compare with Device Management.

Developers often ask questions about device management in dpCtl. Documentation update is needed.

Features to compare:

• Device selection
  cuda.select_device(0), cuda.close()
dpctl.device_context(...)
• Device list
  Not supported in dpCtl yet.

Missing features:

• Support for multi-GPU machines (sort devices by performance) #246 Multi-GPU machines
• Functions for selecting current device #247 Functions for selecting device
• Functions for enumerating devices #248 Device list