[server] Add a skeleton of RestResourceIssueTracker
[FaceRest::ResourceHandler] Add a new member function replyHttpError()
[RestResourceIssueTracker] Use replyHttpStatus()
[RestResourceIssueTracker] Fix a wrong function name in previous commit

replyHTTPError ->
replyHttpStatus
[server] Add new privileges for treating IssueTracker & IssueSender action
[DBClientConfig] Use OPPRVLG_CREATE_ISSUE_SENDER instead of OPPRVLG_CREATE_SERVER to limit creating IssueTracker
[DBClientConfig] Use OPPRVLG_GET_ALL_ISSUE_SENDER to limit getting IssueTracker
[server] Rename privilege names for treating issue related settings

OPPRVLG_*_ISSUE_SENDER ->
OPPRVLG_*_ISSUE_SETTING
[OperationPrivilege] Add member functions to add/remove flags
[OperationPrivilege] Add static functions to add/remove a flag
[testDBClientConfig] Use OperationPrivilege::removeFlag()
[UnifiedDataStore] Add wrapper functions to treat IssueTracker
[RestResourceIssueTracker] Add initial implementation of handleGet()
Merge pull request #264 from project-hatohol/rest-resource-issue-tracker

Add operation privilege types for issue settings