One-key 4G conference and add multi-participants support

IMS: Add APIs to get intent for conference dialer

1) Add config to control the conference dialer by MCC/MNC.
3) Start confer dialer to originate a conference call.
4) Start confer dialer to add participants for the existing conference call.
5) Show 4G conference call option only if IMS is registered.

Change-Id: Ieb89e43dbd0cec13c89af332d7923d181d92b23a

IMS: Show conference participant state

1) Add config to control the conference state display.
2) Show conference participant state according to the config value.
3) Add more states for conference call.

Change-Id: I75919d0538d2990c161a393d47ceacaf7cbcf805

IMS: Implement adding multi-participants to an exsiting conference call

1) Add a config value to enable or disable of adding
   multi-participants to conference call.
2) Format intent with current participants to start ConfernceDialer.
3) Config to add participant only in conferencall call for CMCC.
4) Format participants' numbers before sending add multi
   participants intent to ConferenceCallActivity.

Change-Id: Ibcbfd2b26801686de2abb6f2940c97487b20b424

IMS: Enable entry 4G conference call in Dialer

1) Start conference call in dialtact.
2) Start conference call in dialpad with numbers.
3) Show 4G conference call option only if IMS is registered.

Change-Id: I9f9c379e26b904f7749a72241e51cc6660f98d53
CRs-Fixed: 934253