hostapd: Per STA config knob framework

The change list has below changes,
- Init and deinit of the Per STA configuration
- Parsing the config file and user inputs
- Adding, deleting and retriving Per STA entry from config file
- Updating assoc resp frame with configured params

This framework would be useful in debugging the IOP issues.
This will expose configuration option thaat can be configured
dynamically from cloud. Which can be used to enable/disable
the per station params.

BUG=b:63396880
TEST=Sanity test on hostapd
- Verifed the commands, sta_policy_add, sta_policy_del
  and sta_policy_get to ADD, DEL and GET per STA config value.
- Stability Test: Repetedly calling command to set, get and del
  in loop. Parellaly doing start and stop on hostapd, to make
  make sure there are no crash
- Syntax:
  sta_policy_add <sta_id=mac> <param=val>
  sta_policy_get <sta_id=mac>
  sta_policy_del <sta_id=mac>

Sanity test on wpa_supplicant:
- Verified wpa_supplicant for successful compilation
- Verified mesh networks is successful
- Verified Child node works in station mode by disabling
  ap-group-monitor

CQ-DEPEND=CL:*414368, CL:619047

Change-Id: I0754cbc6783242cffd955b0ce188f8c38f0c6009
Reviewed-on: https://chromium-review.googlesource.com/575316
Commit-Ready: Srinivasa duvvuri <sduvvuri@google.com>
Tested-by: Ratheesh S P <ratheesh.sp@globaledgesoft.com>
Reviewed-by: Srinivasa duvvuri <sduvvuri@google.com>
12 files changed