Time interpolation of input data with XIOS temporal type

[EdHone]

Are there any linked Issues or Pull Requests?

No response

Brief description

Follows #230
Blocked by #231

Continues LFRic trac ticket #4606.
Building on the previous work above this issue will implement simple first-order interpolation of input data within the new temporal controller object. This will be mostly taken from the existing time_axis class in lfric_xios.

Further details of the issue.

No response

[EdHone]

Blocked by #231

Development underway on branch: https://github.com/EdHone/lfric_core/tree/242-temporal-interp

Implementation appears completely functional - more tests needed to iron out edge cases etc.