LP#1857150: eg-fm-record-editor: support field-level help popovers

LP#1857150: eg-fm-record-editor: support field-level help popovers

Add a new helpText field option to supply text for help popovers
that display next to the field label.

Example usage:

<eg-string #hostHelpStr text="EDI FTP or SCP server, including protocol. For example, ftp://ftp.example.org." i18n-text></eg-string>

<eg-fm-record-editor #editDialog
  idlClass="acqedi"
  [fieldOptions]="{
                    host: {helpText: hostHelpStr},
                  }"
</eg-fm-record-editor>

Sponsored-by: Evergreen Community Development Initiative
Signed-off-by: Galen Charlton <gmc@equinoxinitiative.org>