Allow trigger node delay to be overridden with msg.delay

[knolleary]

• New feature (non-breaking change which adds functionality)

Proposed changes

Allow the delay between first and second messages sent by Trigger node to be set per-message using msg.delay.

This does not apply to the looping mode.

Checklist

• I have read the contribution guidelines
• For non-bugfix PRs, I have discussed this change on the forum/slack team.
• I have run grunt to verify the unit tests pass
• I have added suitable unit tests to cover the new/changed functionality

[dceejay]

Works as implemented. Tests cover single topic use case - should they be extended to include per topic case ?
Happy to merge either way.

[dceejay]

@kazuhitoyokoi - are you able to add a translation for packages/node_modules/@node-red/nodes/locales/en-US/messages.json line 323 ? And maybe the .info part of the .html file also ?
Many thanks

[knolleary]

I've updated it to also support overriding the loop interval. Look okay to you @dceejay ?

[dceejay]

Works great. Feel free to merge

[kazuhitoyokoi]

@dceejay I will submit Japanese translations for the trigger node tomorrow.