Adds CLI to copy attributes from one NetCDF file to another.

[MoseleyS]

Adds CLI to copy attributes from one NetCDF file to another. Includes acceptance test.

Addresses https://github.com/MetOffice/epp_workflows/pull/24

For the EPP Precipitation Type workflow, we need a new CLI to copy attribute values from one cube to another so that the precipitation type output can contain StaGE attribute values inherited from a precipitation rate cube.

Acceptance test data can be found in https://github.com/metoppv/improver_test_data/pull/41

Testing:

• [x] Ran tests and they passed OK
• [x] Added new tests for the new feature(s)

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (6f1593a) 98.40% compared to head (6232168) 98.40%.

:exclamation: Current head 6232168 differs from pull request most recent head 5a67ecc. Consider uploading reports for the commit 5a67ecc to get more accurate results

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1976 +/- ## ======================================= Coverage 98.40% 98.40% ======================================= Files 124 124 Lines 12067 12067 ======================================= Hits 11874 11874 Misses 193 193 ```

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