Implement actions artifacts (#22738)

Implement action artifacts server api.

This change is used for supporting
https://github.com/actions/upload-artifact and
https://github.com/actions/download-artifact in gitea actions. It can
run sample workflow from doc
https://docs.github.com/en/actions/using-workflows/storing-workflow-data-as-artifacts.
The api design is inspired by
https://github.com/nektos/act/blob/master/pkg/artifacts/server.go and
includes some changes from gitea internal structs and methods.

Actions artifacts contains two parts:

- Gitea server api and storage (this pr implement basic design without
some complex cases supports)
- Runner communicate with gitea server api (in comming)

Old pr https://github.com/go-gitea/gitea/pull/22345 is outdated after
actions merged. I create new pr from main branch.


![897f7694-3e0f-4f7c-bb4b-9936624ead45](https://user-images.githubusercontent.com/2142787/219382371-eb3cf810-e4e0-456b-a8ff-aecc2b1a1032.jpeg)

Add artifacts list in actions workflow page.

models/migrations/migrations.go

@@ -491,6 +491,8 @@ var migrations = []Migration{
 	NewMigration("Add ArchivedUnix Column", v1_20.AddArchivedUnixToRepository),
 	// v256 -> v257
 	NewMigration("Add is_internal column to package", v1_20.AddIsInternalColumnToPackage),
+	// v257 -> v258
+	NewMigration("Add Actions Artifact table", v1_20.CreateActionArtifactTable),
 }
 
 // GetCurrentDBVersion returns the current db version