fix: mount notification email templates

[singh-inder]

What kind of change does this PR introduce?

Bug fix #4783

Follow up: #4400

What is the current behavior?

When running supabase start, only auth email templates were mounted in kong and configured in auth service.
Notification email templates were ignored.

What is the new behavior?

Notification email templates are now mounted in Kong, and the required env vars for notification templates are configured in the auth service.

[coveralls]

Pull Request Test Coverage Report for Build 21596281528

Details

• 6 of 30 (20.0%) changed or added relevant lines in 1 file are covered.
• 5 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.06%) to 55.307%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
internal/start/start.go	6	30	20.0%

Files with Coverage Reduction	New Missed Lines	%
internal/gen/keys/keys.go	5	12.9%

Totals
Change from base Build 21594645043:	-0.06%
Covered Lines:	7118
Relevant Lines:	12870

---

💛 - Coveralls

[singh-inder]

@sweatybridge sorry for the tag, would you mind taking a look at this as well? A couple of users are stuck on it.

Also, kind of related: supabase/supabase#41860 (comment), its about how auth template paths (if not absolute) are expected to be relative to a level above builder.SupabaseDirPath but not notification templates. I also notice there is a FIXME comment next to code building auth template path. I assume that auth template path will only be fixed in the next major version but until then it might be better if notification template paths used the same base for consistency.

cli/pkg/config/config.go

Lines 697 to 710 in 3fe548f

	for name, tmpl := range c.Auth.Email.Template {
	// FIXME: only email template is relative to repo directory
	cwd := filepath.Dir(builder.SupabaseDirPath)
	if len(tmpl.ContentPath) > 0 && !filepath.IsAbs(tmpl.ContentPath) {
	tmpl.ContentPath = filepath.Join(cwd, tmpl.ContentPath)
	}
	c.Auth.Email.Template[name] = tmpl
	}
	for name, tmpl := range c.Auth.Email.Notification {
	if len(tmpl.ContentPath) > 0 && !filepath.IsAbs(tmpl.ContentPath) {
	tmpl.ContentPath = filepath.Join(builder.SupabaseDirPath, tmpl.ContentPath)
	}
	c.Auth.Email.Notification[name] = tmpl
	}