An update of check-manifest shone some light on some issues with MANIFEST.in, specifically that we didn't ignore/prune the contrib directory, and that we were using prune instead of exclude for files. This fixes both issues.

Fixes #7403

... after it got borked by #6081

I don't think its useful, and I don't even know where it would end up.

* Add a sytest blacklist file

* Add changelog

* Add blacklist to manifest

* Tweak code coverage settings

* Fix manifest

* Newsfile

* Fix commit status?

Signed-off-by: Aaron Raimist <aaron@raim.ist>

move the example email templates into the synapse package so that they can be
used as package data, which should mean that all of the packaging mechanisms
(pip, docker, debian, arch, etc) should now come with the example templates.

In order to grandfather in people who relied on the templates being in the old
place, check for that situation and fall back to using the defaults if the
templates directory does not exist.

PR #2413 added an issue template, but just adding files to the project
directory upsets the packaging scripts: we need to explicitly include or
exclude them.

Move the template into a .github directory to make that easy, and to de-clutter
the root a bit.

* Factor out some of the code shared between the different sytest jenkins scripts

* Exclude jenkins from the MANIFEST

* Fix dendron build

* Missing new line

* Poke jenkins

* Export the PORT_BASE and PORT_COUNT

* Poke jenkins