gz sdf --print should be able to print auto-computed inertial values

[scpeters]

Desired behavior

We should add a command-line option to gz sdf --print that will replace <inertial auto="true"/> elements with the explicit, auto-computed inertial values. This will only work for simple shapes, but this could potentially be extended by a gz sim command.

Alternatives considered

Implementation suggestion

Add a configuration to the PrintConfig class to configure whether to expand auto-inertial elements with explicitly computed inertial values and a corresponding command-line option to gz sdf --print.

For example:

• bool PrintConfig::ExpandAutoInertials() const
• void PrintConfig::SetExpandAutoInertials(bool)
• gz sdf --print <file> --expand-auto-inertials

For shapes that don't have a way to compute auto-inertials (such as mesh), they should either print the default inertial values or retain the <inertial auto="true"/> element.

Additional context

[azeey]

The ConfigureResolveAutoInertials enum might be a good place to add another option where the computed inertia is written back to the ElementPtr that corresponds to the <inertial> tag. Then gz sdf --print would just set the ParserConfig (not PrintConfig) with this new option. Using the PrintConfig directly will probably be tricky because where that config is used, we don't have the computed inertia readily available.

[scpeters]

see also the discussion in #1335 (comment)

[scpeters]

this feature will help me with other work, so I've attempted to implement it in #1422

[scpeters]

implemented for simple shapes (not meshes) in #1422. A similar command could be implemented in gz-sim to print mesh inertial data.