Added mailing thing and mails when account created or edited

example.env

package-lock.json

package.json

src/lib/config.js

src/lib/server/mailer.js

src/lib/server/models/User.ts

src/routes/(admin)/users/[id=integer]/+page.server.js

src/routes/(admin)/users/create/+page.server.js

src/routes/(admin)/users/create/+page.svelte