Enhanced configuration discovery for cargo install and cargo uninstall commands

[jofas]

This PR orthogonalizes the behaviour concerning configuration resolution of cargo uninstall with cargo install. Namely, both should ignore local configuration and only consider $CARGO_HOME/config.toml as configuration.

This PR is draft with the following still open:

• since this PR already changes the configuration discovery of cargo uninstall, we could also make the configuration discovery of cargo install more intuitive by changing it from "start configuration discovery at $CARGO_HOME/config.toml" to "only consider global configuration in $CARGO_HOME/config.toml."

  See here:

  cargo/src/bin/cargo/commands/install.rs

  Lines 93 to 94 in efd3733

  	// TODO: Consider calling set_search_stop_path(home).
  	config.reload_rooted_at(config.home().clone().into_path_unlocked())?;

  The same should then be done for the cargo uninstall command

• rebase so the changes to the man-page of cargo install made in Added documentation for the configuration discovery of cargo install to the man pages #11763 can be enhanced

• update man-page documentation of the configuration discovery behaviour of cargo install and cargo uninstall commands

• since this PR is a breaking change, a different PR with warning messages for future breaking changes is needed to land first: Warnings for breaking changes to the configuration discovery of cargo install and cargo uninstall proposed in #11775 #11786

• once Warnings for breaking changes to the configuration discovery of cargo install and cargo uninstall proposed in #11775 #11786 lands, rebase this branch and revert the changes made in that PR

For more information see discussions in:

• cargo install does not respect .cargo/config.toml #11660
• Added documentation for the configuration discovery of cargo install to the man pages #11763

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