SpiNNman simulation

[Christian-B]

Note: There is a parallel SpiNNManSimulation as it is tested by these prs.

This was motivate by SpiNNMan scripts not allowing but not needing a user cfg.

An alternative would have been to error only if required cfg stuff was missing,
But there are many different rules so this would need to be a delayed exception stored to call later

in this alternative the rule is IF there is a template a user cfg is required.
IE anything that depends on SpiNNFrontEndCommon

The addition is an extra slot value template and a add_template method to add it
The code then checks for it and acts differently if found.

While there there was some cleanup.

• Code to look for a template replaced with use stored value

• Code to find user cfg -simplified to find one, None or error

  • Multiple user cfg unlikely to be ever used and would cause more confusion than help
  • Move to config_holder which has the data required

• config_loader extra method to just load the defaults

• config_loader load_config now takes the usercfg as a path not filename

• config_holder now decides about the user cfg

  • If present it is read
  • If there is a template call the moved install_cfg_and_error
  • if neither user cfg nor template just read the defaults

  test_conf_loader adapted accordingly
  -@pytest.mark.xdist_group forces all these test to be run sequentially as they use a method that depends on global values

  • ref: https://pytest-xdist.readthedocs.io/en/stable/distribution.html

must be done at the same time as:

[Christian-B]

Part of the work to run SpiNNman level simulations and lots of cleanup through a matching branch