facilitate browsers' autofill by form field names

[KiaraGrouwstra]

Is your feature request related to a problem? Please describe.
Filling forms is a chore. Ideally, we should facilitate people in this to improve the user experience.

Describe the solution you'd like
Browsers help people remember both addresses, as well as previous form fills, for the purpose of autofilling form fields based on their name attribute.
We should therefore facilitate such attribute be set on form fields created in nextcloud forms to support such autofilling by people filling out a form created in nextcloud.

Describe alternatives you've considered
web forms by custom html, rather than made by nextcloud forms

Additional context
Tackling will also be helpful:

• Add technical identifier / name for fields #1040, as both need for some technical names to be supported internally (separating these names could perceivably be possible, if perhaps not low-hanging fruit)
• Prefill fields from url-parameters #638, as query parameters will want some kind of name, in which case semantically helpful names would seem preferable