Email translation improvements

[aatkin]

partially implements #3241

• Implements named parameters for email templates
• English localizations have been updated for reference (with both named/vector parameters)
• Updated com.taoensso/tempura to latest and fixed the issue preventing update before
• Removed format parameter checks and tests, these should be re-implemented

Extra translations for email templates can use vector parameters for backwards compatibility and transition period into named parameters. These two localization strings should work identically:

;; :t.email.application-approved/message-to-applicant
"Dear %:recipient%,\n\nYour application %:application-id% has been approved.\n\nYou can view the application and the decision at %:application-url%"
"Dear %1,\n\nYour application %3 has been approved.\n\nYou can view the application and the decision at %6"

Mixing formats is not allowed:

;; will throw runtime error
"Dear %1,\n\nYour application %:application-id% has been approved.\n\nYou can view the application and the decision at %:application-url%"

Checklist for author

Remove items that aren't applicable, check items that are done.

Reviewability

• [x] Link to issue

Backwards compatibility

• [x] Config is backwards compatible. Extra translations may use vector parameters, and should be flexible to transition into named parameters.

Documentation

• [x] Update changelog if necessary

Testing

• [x] Complex logic is unit tested

Follow-up

• [ ] New tasks are created for pending or remaining tasks