Add support to disable ModuleInfo generation based upon import path

[rikkimax]

Preference to merging should go to: #20899
I need it a lot more.

This is a preparation PR, to make ModuleInfo generation be dependent on the import path switch.

It is to help codebases that are mixed -betterC and full D.

See any of the bindbc codebases for why it is absolutely abhorrent that it is an all or nothing switch, rather than recognizing its pay as you go runtime scale nature.

https://github.com/BindBC/bindbc-sdl/blob/master/dub.json

[dlang-bot]

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If your PR contains non-trivial changes, please reference a Bugzilla issue or create a manual changelog.

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub run digger -- build "master + dmd#20947"

[rikkimax]

LINK : fatal error LNK1000: unknown error at 00007FF7B4E59F06; consult documentation for technical support options

Welp I haven't seen that one before

[rikkimax]

Or:

Error: error: git-remote-https died of signal 10
Error: fatal: remote helper 'https' aborted session

It really doesn't want to go in!