Add option to stop shimming packages installed with tools managed by asdf

### Is your feature request related to a problem? Please describe

With asdf v0.14, I don't believe asdf shimmed executables that I did not explicitly tell it to shim. Now, asdf v0.18 is automatically shimming packages installed by go, npm, etc. This has created a headache for me as I had specific tools on my path which were generated by specific versions of go, node, etc. I specifically want to use a single tool version's package globally, for everything. The auto-shimming behavior of asdf v0.18 breaks this.

See related issues that could also be resolved by providing an option to restore the old behavior:
- https://asdf-vm.com/more/faq.html#why-is-a-command-completely-unrelated-to-the-plugins-i-m-using-is-getting-shimmed-by-asdf
- https://github.com/asdf-vm/asdf/issues/584
- https://github.com/asdf-vm/asdf/issues/1955

EDIT: this may not be related to asdf v0.18 vs v0.14..., I am seeing python packages are shimmed by asdf v0.14. Maybe this is related to the plugins? I am not seeing go or npm packages being shimmed by v0.14

### Describe the proposed solution

I would like to see some config option to restore the asdf v0.14 behavior and stop shimming packages installed by tools managed by asdf.

### Describe similar `asdf` features and why they are not sufficient
N/A

### Describe other workarounds you've considered

I have to delete the shims and copy the executables I want to use globally out to shared bin folders like `~/.local/bin`

The issue names no source files, tests, or entry points. Start by locating asdf's shim-generation and configuration entry points, then trace how packages from Go, npm, and Python tools are discovered. Done means a documented option can restore the older non-auto-shimming behavior, with tests covering the configuration and resulting shim set.

Written by the indexing model from the issue text.