Rollup merge of #141909 - Shourya742:2025-06-01-add-execution-context, r=Kobzol

Add central execution context to bootstrap

This PR continues the effort toward command centralization as outlined in rust-lang/rust#126819. It introduces a centralized execution context through which all commands will be executed. Previously, centralization was limited to build methods; this PR extends it to the `config` module and updates the remaining methods accordingly.

Best reviewed commit by commit.

r? ``@Kobzol``

Author: fmease