Actions Artifacts support uploading multiple files and directories (#24874)

current actions artifacts implementation only support single file
artifact. To support multiple files uploading, it needs:

- save each file to each db record with same run-id, same artifact-name
and proper artifact-path
- need change artifact uploading url without artifact-id, multiple files
creates multiple artifact-ids
- support `path` in download-artifact action. artifact should download
to `{path}/{artifact-path}`.
- in repo action view, it provides zip download link in artifacts list
in summary page, no matter this artifact contains single or multiple
files.

models/migrations/migrations.go

@@ -511,6 +511,8 @@ var migrations = []Migration{
 	NewMigration("Add git_size and lfs_size columns to repository table", v1_21.AddGitSizeAndLFSSizeToRepositoryTable),
 	// v264 -> v265
 	NewMigration("Add branch table", v1_21.AddBranchTable),
+	// v265 -> v266
+	NewMigration("Alter Actions Artifact table", v1_21.AlterActionArtifactTable),
 }
 
 // GetCurrentDBVersion returns the current db version