Add export-to-html menu action to regulatory-statements document view

[elpoelma]

Solves https://binnenland.atlassian.net/jira/software/c/projects/GN/boards/4?modal=detail&selectedIssue=GN-3771.

[abeforgit]

Some notes, which may or may not be an issue:

• table of contents does not get exported
• we lose the lblodgn:ReglementaireBijlagen type, since that type is defined outside the editor root. this is probably fine, and will improve when we rework the way we do types in documents

[elpoelma]

Some notes, which may or may not be an issue:

* table of contents does not get exported

* we lose the `lblodgn:ReglementaireBijlagen` type, since that type is defined outside the editor root. this is probably fine, and will improve when we rework the way we do types in documents

Current the ToC does indeed not yet get exported. I still need to merge the static export feature.

[abeforgit]

imo you can merge without it