LIU-407: Use EAGLE_test_repo as the basis for test graphs

[myxie]

(Note: This relies on files introduced in #278, which is why this is currently targetting that branch. This must be merged after that PR is merged, at which point this should be re-targetted to master. It is probably a good idea to wait for EAGLE test repo PR #2 to merge, too.)

Issue

This PR addresses LIU-407, which aims to create a standardised graph repository for DALiuGE/EAGLE. When we make changes are made to the graph schema/EAGLE graph output, we need to:

a) Update some code in the translator/engine based on those changes, and
b) (Sometimes) update the graphs that are used in the unittests, depending on the changes to the input/translated graphs.

The problem with this is not all unit tests fail when updates occur, and not all unit-tests cover all graphs. This means some graphs will be updated more regularly (e.g. for the translator) and other graphs not regularly (e.g. engine test graphs).

The result of this is that we don't effectively synchronize our graphs to the EAGLE output, and we also have to go through >80 graphs individually, open them in EAGLE, and then save them again, to ensure our tests are accurately testing the correct graph formats. Hence, having all the test graphs in one place, that can be updated more easily and is separate to the DALiuGE and EAGLE repos will improve the consistency of our testing moving forward. It should also help us version and release the schema effectively.

Solution

This PR removes the existing test graphs from DALiuGE, and redirects all the tests cases to the daliuge_tests module that is installed when we install the eagle-test-repo project (established in the corresponding PR in the EAGLE_test_repo).

Now, we install the eagle-test-repo when running a test install of DALiuGE:

$ pip install -e ".[test]"

It is then possible to access the test graphs in the daliuge_tests module:

import daliuge_tests.reproGraphs as test_graphs
from importlib.resources import files

workflow = "apps.graph"
lg_path  = files(test_graphs) / workflow

As a side-effect of these changes, I've also transitioned the unittests away from the deprecated pkg_resources towards importlib.resources

[coveralls]

coverage: 79.627%. remained the same
when pulling 275415d on LIU-407
into 090301a on LIU-402.

[awicenec]

This is an excellent update to the test environment, thanks!