[MM-13747] Add ability to list users to plugin API (#10102)

* add GetUsers in plugin api

* change GetUsers(page int, perPage int) ([]*model.User, *model.AppError) to GetUsers(options *model.UserGetOptions) ([]*model.User, *model.AppError)

* Update GetUsers doc

Co-Authored-By: dom3k <szeptweb@gmail.com>

* Update doc in plugin/api.go

Co-Authored-By: dom3k <szeptweb@gmail.com>

* correct database initialization for the test

* Update plugin/api.go

Co-Authored-By: dom3k <szeptweb@gmail.com>

plugin/plugintest/api.go

@@ -1516,6 +1516,31 @@ func (_m *API) GetUserStatusesByIds(userIds []string) ([]*model.Status, *model.A
 	return r0, r1
 }
 
+// GetUsers provides a mock function with given fields: _a0
+func (_m *API) GetUsers(_a0 *model.UserGetOptions) ([]*model.User, *model.AppError) {
+	ret := _m.Called(_a0)
+
+	var r0 []*model.User
+	if rf, ok := ret.Get(0).(func(*model.UserGetOptions) []*model.User); ok {
+		r0 = rf(_a0)
+	} else {
+		if ret.Get(0) != nil {
+			r0 = ret.Get(0).([]*model.User)
+		}
+	}
+
+	var r1 *model.AppError
+	if rf, ok := ret.Get(1).(func(*model.UserGetOptions) *model.AppError); ok {
+		r1 = rf(_a0)
+	} else {
+		if ret.Get(1) != nil {
+			r1 = ret.Get(1).(*model.AppError)
+		}
+	}
+
+	return r0, r1
+}
+
 // GetUsersByUsernames provides a mock function with given fields: usernames
 func (_m *API) GetUsersByUsernames(usernames []string) ([]*model.User, *model.AppError) {
 	ret := _m.Called(usernames)