Remove mip_concatenate script from cdds/bin

Migrated Jira Issue CDDSO-255
Jira creation date 27/03/2023 12:52
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I think this script should be removed due to the following.

* The ``cdds/bin/mip_concatenate`` script references a ``main_concatenation`` function that no longer, or never did, exist.
* I can’t see any references to the ``mip_concatenate`` script from ``u-ak283`` or elsewhere anyway.

I’d also be tempted to expand the scope of this issue to include making the naming around the ``mip_concatenate`` scripts and their related function names, organisation in ``cdds.convert``, rose app names and commands, and cylc task names, more consistent.
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Start by inspecting cdds/bin/mip_concatenate and searching the repository, including u-ak283, for references to the script and the missing main_concatenation function. The focused outcome is removal of the unused script with no remaining references; any broader naming changes across cdds.convert, Rose apps and commands, or Cylc tasks should be clarified before expanding the work.

Written by the indexing model from the issue text.