Incompatible differences in commands

For [nxp-pac](https://github.com/embassy-rs/nxp-pac) we are slowly migrating to a more stm32-metapac style of generating the code from extracted data, instead of directly generating the code from the SVD. During migration I had the following issue:

The commands `generate`, `extract-all` and `extract-peripheral` work slightly different, resulting in inconsistent output.

For example, the `generate` command uses `svd2ir::convert_svd` whilst `extract_all` and `extract_peripheral` use `svd2ir::convert_peripheral`. In order to generate correct code, `svd2ir::convert_svd` [adds extra module namespaces](https://github.com/embassy-rs/chiptool/blob/e2888bf6404263689b523f92f9cc1b0632945b01/src/svd2ir.rs#L410-L411) in the form of 'regs' and 'vals' to names.

You can clearly note the PAC's generated directly and PAC's that use extraction and then manually generating code by the presence of these names in the namespaces. As an additional consequence, files with transforms for generation may not be directly usable when extracting.

Making it more consistent may require the commands to optionally fall back to their older behaviour.