Add field QUOTA_OCCUPIED and QUOTA_TOTAL to VoicemailContract.Status

Fields to track how much visual voicemail quota is used.

Add field LAST_MODIFIED to VoicemailContract.Voicemails.
Add field LAST_MODIFIED to CallLog.Calls.

Timestamp field for the last time the row is inserted/updated.

+ VoicemailContract.Status.setQuota() helper method to set the quota.

Bug:25197644
Bug:22013880

Change-Id: Icb250203971df1f4ae4e1cbc9dbefeec9ad3282e