refactor: extract inlined dkim options to config file

config/dkim.json

@@ -0,0 +1,5 @@
+{
+	"domainName": "cohabit.fr",
+	"keySelector": "sendmailY2024M03",
+	"privateKey": "/etc/ssl/certs/dkim_keys/dkimMailKey.pem"
+}

src/transporter.ts

@@ -1,9 +1,9 @@
 // @deno-types="npm:@types/nodemailer"
 import nodemailer from 'nodemailer'
+import dkim from '../config/dkim.json' with { type: 'json' }
 
 export async function transporter() {
-	const dkimPath =
-		'/home/julien/dkim_sendmail_keys/dkim_sendmail_cohabit_fr.pem'
+	const dkimPath = dkim.privateKey
 	const dkimPrivateKey = await Deno.readTextFile(dkimPath).catch((cause) => {
 		throw new Error(`unable to load DKIM private key from "${dkimPath}"`, {
 			cause,
@@ -15,8 +15,8 @@ export async function transporter() {
 		newline: 'unix',
 		path: '/usr/sbin/sendmail',
 		dkim: {
-			domainName: 'cohabit.fr',
-			keySelector: 'sendmailY2024M03',
+			domainName: dkim.domainName,
+			keySelector: dkim.keySelector,
 			privateKey: dkimPrivateKey,
 		},
 	})