tasks #6660: renderer table headers in artifact link

Use both #id and .classname to specify the style of a rendere table
header. While the .classname is enough in widgets and artifact link
field, we need to keep the #id to override bootstrap issue with nested
tables.

Change-Id: I6e6c8f1ff0c19c255e3929551c6a482091c6203a
request #6662: Fix Mediawiki UI in experimental theme

Change-Id: I9e0f45db18eac76c57a6532d8d1854b02b235322
Merge commit 'refs/changes/71/2271/1' of ssh://gerrit.tuleap.net:29418/tuleap into stable

* ssh://gerrit.tuleap.net:29418/tuleap:
  tasks #6660: renderer table headers in artifact link
This is Tuleap 6.12.99.31

Change-Id: I4321ae7c0982681d11a0a813e0a1bd2e2b657f5b
Merge commit 'refs/changes/72/2272/2' of ssh://gerrit.tuleap.net:29418/tuleap into stable

* ssh://gerrit.tuleap.net:29418/tuleap:
  request #6662: Fix Mediawiki UI in experimental theme
This is Tuleap 6.12.99.32

Change-Id: I703f48b6b8c4fc917acdb1e7a3a4d3cf4f33e37d