feat: setup email workflows across admins env

[ayush00git]

Closes #44
Closes #74

Changes made -

1. removed adminType from the frontend route as it wasn't necessary.
2. Set up email workflows across the admin environment, thinking to include the user who made the post as well.
   We've used go-routines to send emails to not block any ongoing user query.

			go func() {
				// search for email of ae
				var position models.PositionType
				if post.TypeOfPost == "Civil" {
					position = models.TypeAECivil
				} else {
					position = models.TypeAEElectrical
				}
				var ae models.Admin
				result := h.DB.Where("position = ?", position).Take(&ae)
				if result.Error != nil {
		       	 	log.Printf("failed to send AE mail for post %d", post.ID)
					return
				}
				if err := services.SendPostMailToAdmins(ae.Email, postURL); err != nil {
		       	 	log.Printf("failed to send AE mail for post %d: %s", post.ID, err)
					return
				}
			} ()

3. As the post is created it is directly mailed to the civil/electrical type XEN depending upon the type_of_post field in the post schema.

[ayush00git]

Send a custom message as well to the admins like - completion, closed, review..