feat: allow configuring gitea schema mode (#23)

* config entries for schema change
* remove broken/unused syntetic nodejs action
* specify desired schema in model struct that is read by unmarshal
* replace params by config
* allows gitea context + env names
* act --gitea now parses a subset of gitea specific workflows

Reviewed-on: https://gitea.com/actions-oss/act-cli/pulls/23
Co-authored-by: Christopher Homberger <christopher.homberger@web.de>
Co-committed-by: Christopher Homberger <christopher.homberger@web.de>

cmd/input.go

@@ -66,6 +66,7 @@ type Input struct {
 	validate                           bool
 	strict                             bool
 	parallel                           int
+	gitea                              bool
 }
 
 func (i *Input) resolve(path string) string {