PLT-7: Refactoring api to use translations (chunk 4)

- Translation for api templates english and spanish

api/templates/post_subject.html

@@ -1 +1 @@
-{{define "post_subject"}}[{{.ClientCfg.SiteName}}] {{.Props.TeamDisplayName}} Team Notifications for {{.Props.Month}} {{.Props.Day}}, {{.Props.Year}}{{end}}
+{{define "post_subject"}}[{{.ClientCfg.SiteName}}] {{.Props.Subject}}{{end}}