Mail Activity Board available for v17

[YvesR]

Describe the solution you'd like
In reference to #1251 the module mail_activity_board is ported to v.17.
I checked out this branch and looked into the module.

I see the version name is still 16.x.x.x.x so I changed this to version 17.
In addition the mail_activity_view.xml contains attrs as property for fields, which is not used in v17 anymore.
In a quick local docker test I just removed this properties and after the activation of the module was successful. at first.

But then the url/web portal do not load anymore as there are missing assets now:
http://localhost:8069/web/assets/202cbf3/web.assets_web.min.js is reported 404 , so compilation of the module failed somehow. Restart don't change anything.

Is there something I can do to quick fix this or it just take more time to port this module? In this case the "done" checkbox in #1251 should be unchecked :) .

Any feedback is appreciated.