Add "verify email" sending logic

{"ops":[{"insert":"Send emails, for that “confirm email” on account creation will be used\nCreate simple email HTML template, with styles and text"},{"attributes":{"list":"bullet"},"insert":"\n"},{"insert":"Create logic that allows to take HTML template and process it, get string as result"},{"attributes":{"list":"bullet"},"insert":"\n"},{"insert":"Create email sender service and all corresponding entities"},{"attributes":{"list":"bullet"},"insert":"\n"}]}