[feature]Allow to add custom email template by user

[micker]

Hello for now email template component is a little limited because only dev can add it.
but it a small vision of this great component. I think it can be cool to allow user to create his wanted template and after component can use it.
Why ? imagine a workflow, or a form component
if i want a user create a workflow or a form he can create an email template in general component and 'use it' in other component
it can be very extendable !
what do you think about this ?

• Add new template email
• Choose component
• allow component to 'link' email to sending process