A few improvements to calendar node

[dsl400]

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

Proposed changes

node settings now allows selection of calendar by name instead of pasting in the id or name of the calendar
added ability to get complete list of calendars and filter it

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]

Hi @dsl400,
apologies for not getting to this. Due to another previous PR this now has conflicts... any chance you can resolve them for us and check your PR still works as intended ? And please run grunt to check tests pass... Many thanks

[dceejay]

Very close - sadly we still like { } :-)

and we now seem to have nextStartingEvent defined twice...