Add YAML Linter GHA

[nefrathenrici]

This PR adds a basic YAML linter to keep our config files clean.

Two open questions

• Should this action lint all YAML files, including pipeline.yml?
• Should this action be part of the existing Julia formatter action?

If people like this, I will format the YAML files nicely in this PR as well.

[charleskawczynski]

Looks fine to me, maybe someone else can review this, too?

[Sbozzolo]

Can you post what the diff/output would look like?

[nefrathenrici]

Here is some sample output - it is not as nice as the Julia formatter because it just lints instead of formatting.

I am looking into yamlfmt for actual formatting

[nefrathenrici]

@Sbozzolo I have gotten it to run the diff, here is some sample output below. The workflow log contains color for the diff as well.

--- a/config/gpu_configs/gpu_aquaplanet_diagedmf.yml
+++ b/config/gpu_configs/gpu_aquaplanet_diagedmf.yml
@@ -7,23 +7,23 @@ z_max: 55000.0
 z_elem: 63
 dz_bottom: 30.0
 dz_top: 3000.0
-moist: equil 
-surface_setup: DefaultMoninObukhov 
+moist: equil
+surface_setup: DefaultMoninObukhov
 rad: allskywithclear
 idealized_insolation: false
 dt_rad: 1hours
 dt_cloud_fraction: 1hours
-turbconv: diagnostic_edmfx 
+turbconv: diagnostic_edmfx
 implicit_diffusion: true

[Sbozzolo]

If 90 % of what this code does is removing trailing spaces, I think we should set up something that removes trailing spaces from every file. We have tons of them.