ANTS upgraded to Iris3.4

[arjclark]

After many months of hard work from developers we have finally been able to upgrade ANTS to Iris 3.4 along with more modern versions of the (many) associated python packages.

These changes have been committed to trunk as of ANTS revision: https://code.metoffice.gov.uk/trac/ancil/browser/ants/trunk?... and contrib revision: https://code.metoffice.gov.uk/trac/ancil/browser/contrib/tru...

Changes are, unsuprisingly, extensive. For details see: https://code.metoffice.gov.uk/trac/ancil/ticket/1935 and https://code.metoffice.gov.uk/trac/ancil/ticket/2066

Given the extensive package updates, ancil values may have changed. Testing on our end with the provided examples and preliminary testing in RMED and GMED workflows have not flagged any major issues, with the majority of differences in outputs being at machine precision level. You may find some tasks need their wallclock and/or memory requests tuning from where they were.

Anyone carrying out development work will need to re-branch from the head of trunk to pick up the changes and continue working with the intended environment, as found in the environment.lock file.