Search: Fixes search limits and adds a page parameter (#16458)

* Search: Fixes search limits and adds a page parameter

This adds a page parameter to search api without adding
any major breaking change.

It does at an api validation error when trying to use
a limit beyond 5000. This is a breaking change. We could
remove this and have it only in the docs and describe that this
is a limit that grafana will apply silently.

Fixes #16049

* Fix: Corrected wrong array slice change

* Docs: minor docs fix

* Search: fixed folder tests

* Fixed: Moved limit to correct inner query

* Search: moving limit check and page check

* Search: limit in handler is no longer needed

pkg/api/folder.go

@@ -12,7 +12,7 @@ import (
 
 func GetFolders(c *m.ReqContext) Response {
 	s := dashboards.NewFolderService(c.OrgId, c.SignedInUser)
-	folders, err := s.GetFolders(c.QueryInt("limit"))
+	folders, err := s.GetFolders(c.QueryInt64("limit"))
 
 	if err != nil {
 		return toFolderError(err)