Add the API for search files (#15605)

* Adding search files api

* Fixing golangci-lint

* Adding bulk-indexing and improving a bit the name indexing for bleve and elasticsearch

* Add content extraction config migration

* Fixing a problem with document extraction

* Unapplying certain changes moved to other PR

* Fixing tests

* Making extract content app migration a private method

* Addressing PR review comments

* Addressing PR review comments

* Adding feature flag

* Removing debug string

* Fixing imports

* Fixing linting errors

* Do not migrate the config if the feature flag is not enabled

* Fix tests

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

model/client4.go

@@ -3044,6 +3044,25 @@ func (c *Client4) GetPostsAroundLastUnread(userId, channelId string, limitBefore
 	return PostListFromJson(r.Body), BuildResponse(r)
 }
 
+// SearchFiles returns any posts with matching terms string.
+func (c *Client4) SearchFiles(teamId string, terms string, isOrSearch bool) (*FileInfoList, *Response) {
+	params := SearchParameter{
+		Terms:      &terms,
+		IsOrSearch: &isOrSearch,
+	}
+	return c.SearchFilesWithParams(teamId, &params)
+}
+
+// SearchFilesWithParams returns any posts with matching terms string.
+func (c *Client4) SearchFilesWithParams(teamId string, params *SearchParameter) (*FileInfoList, *Response) {
+	r, err := c.DoApiPost(c.GetTeamRoute(teamId)+"/files/search", params.SearchParameterToJson())
+	if err != nil {
+		return nil, BuildErrorResponse(r, err)
+	}
+	defer closeBody(r)
+	return FileInfoListFromJson(r.Body), BuildResponse(r)
+}
+
 // SearchPosts returns any posts with matching terms string.
 func (c *Client4) SearchPosts(teamId string, terms string, isOrSearch bool) (*PostList, *Response) {
 	params := SearchParameter{