[MM-43917] Cloud Freemium limits API: messages/posts (#20152)

* WIP - Add api and app funcs

* Add test cases

* Add utils testcases

* Exclude deleted posts

* Add doc for func

* Move api from cloud to usage

* Allow api access to authenticated users

* Change int to int64

* Fix lint issue

* Simplify err check

Co-authored-by: Ashish Bhate <ashish.bhate@mattermost.com>

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>
Co-authored-by: Ashish Bhate <ashish.bhate@mattermost.com>

utils/utils.go

@@ -5,6 +5,7 @@ package utils
 
 import (
 	"io/ioutil"
+	"math"
 	"net"
 	"net/http"
 	"net/url"
@@ -215,3 +216,16 @@ func IsValidMobileAuthRedirectURL(config *model.Config, redirectURL string) bool
 	}
 	return false
 }
+
+// RoundOffToZeroes converts all digits to 0 except the 1st one.
+// Special case: If there is only 1 digit, then returns 0.
+func RoundOffToZeroes(n float64) int64 {
+	if n >= -9 && n <= 9 {
+		return 0
+	}
+
+	zeroes := int(math.Log10(math.Abs(n)))
+	tens := int64(math.Pow10(zeroes))
+	firstDigit := int64(n) / tens
+	return firstDigit * tens
+}