Run LFRic-XIOS technical tests with XIOS 3

### Are there any linked Issues or Pull Requests?

_No response_

### Brief description

A key step towards compatibility with current and future versions of XIOS (XIOS 3) is the ability to run all tests and applications within LFRic_core with either XIOS2 or XIOS3. This issue aims to get the lfric_xios integration and unit tests to work with XIOS 3.

### Further details of the issue.

There are several issues with running LFRic with XIOS 3, some of which appear linked to output post-processing (addressed in PR #204). Others include new requirements for configuration options and certain iodef.xml options which need to be correct for XIOS3. These updates should all be backwards compatible with XIOS2.