[device] 1. Add fan control for as7116-54x ...

[simonJi2018]

- What I did

1. Add fan control for as7116-54x
2. Modify sfputil.py to support sfp insert and remove events for as7116-54x
3. Modify port_config.nps to set port default admin down
4. Modify port_config.ini for add speed attr
5. Code format optimization like remove newline
6. Modify buffers_defaults_t0 and t1, change ingress_lossless_pool mode from dynamic to static
7. Add nephos_dac.nps and nephos_opt.nps for support difference dac and fiber module
   - How I did it
8. Add fan control for as7116-54x
9. Modify sfputil.py to support sfp insert and remove events for as7116-54x
10. Modify port_config.nps to set port default admin down
11. Modify port_config.ini for add speed attr
12. Code format optimization like remove newline
13. Modify buffers_defaults_t0 and t1, change ingress_lossless_pool mode from dynamic to static
14. Add nephos_dac.nps and nephos_opt.nps for support difference dac and fiber module
    - How to verify it
    have test it
    - Description for the changelog

- A picture of a cute animal (not mandatory but encouraged)