MM-17912: Allow searching for files through plugin API (#13647)

* constants and options for getting files

* Method to get files with options

* Add i18n strings for en

* Add API methods for getting files with options

* gofmt -s file

* explicitly set create at in tests

* use greater than nanosecond time difference for tests

* use gte instead of gt for getting files by created time

* use created at time as default sort order for getting file infos

* use explicit inline strings instead of format strings

* join tables only when required

* use if as secondary sort, and update tests

* update field docs to reflect previous changes

* make page and perPage get options as required

* add json struct tags to GetFileOptions

* bump minimum server versioni

* remove sorting by username and channelname

* use bool for sort order type

* use FileInfo prefix instead of just File

* clearer comments

* use zero-based page numbering

* test filtering by user and channel

* remove unnecessary whitespace

* use int instead of uint for page and perPage arguments

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

app/file.go

@@ -1097,6 +1097,10 @@ func (a *App) GetFileInfo(fileId string) (*model.FileInfo, *model.AppError) {
 	return a.Srv().Store.FileInfo().Get(fileId)
 }
 
+func (a *App) GetFileInfos(page, perPage int, opt *model.GetFileInfosOptions) ([]*model.FileInfo, *model.AppError) {
+	return a.Srv.Store.FileInfo().GetWithOptions(page, perPage, opt)
+}
+
 func (a *App) GetFile(fileId string) ([]byte, *model.AppError) {
 	info, err := a.GetFileInfo(fileId)
 	if err != nil {