[1 July 2021] Rename "Reference Number" to "Response ID"

[mantariksh]

This standardises the user-facing terminology we use for submission IDs. This involves the following changes:

Current state	After renaming (1 Jul 2021)
[Email mode] Email subject of received responseEmail subject today ends with (Ref: 123456789), where 123456789 is an example reference number / response ID.	[Email mode] Email subject of received responseEmail subject will end with (#123456789) instead, where 123456789 is an example reference number / response ID.
[Email mode] Email body of received responseThe first field of the emailed response is “Response Number”.“Reference Number” is the field name in the JSON at the bottom of the email.	[Email mode] Email body of received responseThe first field of the emailed response will be renamed ‘Response ID’.JSON at the bottom of the email will display ‘Response ID’ instead of ‘Reference Number’.
[Storage mode] Data tab > ResponsesThe summary table of responses shows ‘Ref no.’ as the header.Individual response pages display a ‘Reference number’ above the timestamp.	[Storage mode] Data tab > ResponsesThe summary table of responses will show ‘Response ID’ as the header.Individual response pages will display ‘Response ID’ instead of ‘Reference number’ above the timestamp.
[Storage mode] Downloaded csv of responses‘Reference number’ is the header of the first column.	[Storage mode] Downloaded csv of responsesThe first column’s header will show ‘Response ID’ instead of ‘Reference number’.
[Storage mode] [Webhooks] Response data sent to 3rd party system via webhooksThe key ‘submissionId’ corresponds to the reference number / response ID.	[Storage mode] [Webhooks] Response data sent to 3rd party system via webhooksNo change here. The key ‘submissionId’ still corresponds to the reference number / response ID.

For form respondents (May 2021)

• Thank you page: 'Response ID: 123456789' (example) will be added before the Submitted timestamp on the Thank you page seen after response submission.
• Email confirmation: 'Response ID: 123456789' (example) will be added to the top of the email body in every email confirmation sent to respondents.
• Email confirmation with pdf response: The field 'Reference Number' will be renamed 'Response ID' in both the email body and attached pdf.

[mantariksh]

branch with these changes is called feat/response-id, to be released on 1 Jul 2021