We don't need to duplicate so many patterns in so many
files since we have a monorepo (and want to keep it).
If I managed to miss something or remove something that
should stay, please put it back. Note that monorepo-wide
patterns should go in the top-level .gitignore file.
Other .gitignore files are for application or folder-
specific patterns.
Previously it was not possible to see code coverage for the majority of
test cases: integration tests that create RabbitMQ nodes.
It was only possible to see code coverage for unit tests.
This commit allows to see code coverage for tests that create RabbitMQ
nodes.
The only thing you need to do is setting the `COVER` variable, for example
```
make -C deps/rabbitmq_mqtt ct COVER=1
```
will show you coverage across all tests in the MQTT plugin.
Whenever a RabbitMQ node is started `ct_cover:add_nodes/1` is called.
Contrary to the documentation which states
> To have effect, this function is to be called from init_per_suite/1 (see common_test) before any tests are performed.
I found that it also works in init_per_group/1 or even within the test cases themselves.
Whenever a RabbitMQ node is stopped or killed `ct_cover:remove_nodes/1`
is called to transfer results from the RabbitMQ node to the CT node.
Since the erlang.mk file writes a file called `test/ct.cover.spec`
including the line:
```
{export,".../rabbitmq-server/deps/rabbitmq_mqtt/cover/ct.coverdata"}.
```
results across all test suites will be accumulated in that file.
The accumulated result can be seen through the link `Coverage log` on the test suite result pages.
Thus, we do not use to clone and build org.eclipse.paho.client.mqttv3,
nor we depend on a local clone of rabbitmq-java-client.
While here, move all java_SUITE-specific files to `java_SUITE_data`.