Add tree.order option

[befriendabacterium]

Allows you to reorder trees to custom order whilst keeping other things synced (e.g. k labels)

[codecov[bot]]

Codecov Report

Patch coverage: 50.00% and project coverage change: -0.04% :warning:

Comparison is base (e837246) 60.48% compared to head (39e0d93) 60.45%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #40 +/- ## ========================================== - Coverage 60.48% 60.45% -0.04% ========================================== Files 9 9 Lines 615 617 +2 ========================================== + Hits 372 373 +1 - Misses 243 244 +1 ``` | [Files Changed](https://app.codecov.io/gh/daniel1noble/orchaRd/pull/40?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Daniel+Noble) | Coverage Δ | | |---|---|---| | [R/orchard\_plot.R](https://app.codecov.io/gh/daniel1noble/orchaRd/pull/40?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Daniel+Noble#diff-Ui9vcmNoYXJkX3Bsb3QuUg==) | `72.72% <50.00%> (-0.39%)` | :arrow_down: |

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[daniel1noble]

This is failing a bunch of checks @befriendabacterium. I haven't looked too deeply into what these are so I'm not merging at the moment