Evaluate removal of docx-mailmerge

[open-dynaMIX]

docx-mailmerge is unsupported. There is a forked successor docx-mailmerge2, but we're still on an unsupported version.

It needs to be discussed if we need to still support mailmerge-templates. In most (all?) projects we use docx-template with the jinja2-syntax.

[trowik]

As long as there is no use case where docx-mailmerge can't be replaced with docx-template+jinja2-syntax, I think we could drop docx-mailmerge.

If there's a case where we need docx-mailmerge, I'd say we should switch to the forked successor, hoping that the successor will be further supported.

[open-dynaMIX]

AFAIK we don't have any projects that use docx-mailmerge. If we can confirm this, we can safely drop support for it.