Influxdb secret engine built-in plugin (#5924)

* intial work for influxdb secret plugin

* fixed typo

* added comment

* added documentation

* added tests

* fixed tests

* added vendoring

* minor testing issue with hardcoded values

* minor fixes

plugins/database/influxdb/influxdb-database-plugin/main.go

@@ -0,0 +1,21 @@
+package main
+
+import (
+	"log"
+	"os"
+
+	"github.com/hashicorp/vault/helper/pluginutil"
+	"github.com/hashicorp/vault/plugins/database/influxdb"
+)
+
+func main() {
+	apiClientMeta := &pluginutil.APIClientMeta{}
+	flags := apiClientMeta.FlagSet()
+	flags.Parse(os.Args[1:])
+
+	err := influxdb.Run(apiClientMeta.GetTLSConfig())
+	if err != nil {
+		log.Println(err)
+		os.Exit(1)
+	}
+}