Add --exclude-packages to pip compile/install/tool install

[terror]

Part of #16771

This diff introduces --exclude-packages to pip {compile, install, tool install}, accepting comma-delimited package names (with --exclude-package as an alias) to exclude packages without an excludes file.

[zanieb]

I think we need to copy the additional content from --excludes above.

When a package is excluded, it will be omitted from the dependency list entirely and its own dependencies will be ignored during the resolution phase

[zanieb]

I'd also just say "Exclude the given packages from resolution".

We'll often also say something like "May be provided multiple times or multiple values can be provided separated by commas"

[zanieb]

I need to think a bit more about what we want long-term, i.e., if we want to go this route or something like --exclude / --exclude-file long-term. I'm wary of adding more options without a clear plan since it'll just make it harder.

Otherwise, this looks good!

[terror]

I need to think a bit more about what we want long-term, i.e., if we want to go this route or something like --exclude / --exclude-file long-term. I'm wary of adding more options without a clear plan since it'll just make it harder.

Otherwise, this looks good!

I'm more a fan of what you just mentioned, i.e. --exclude / --exclude-file. IMO, the generic --exclude taking package names makes a bit more sense here.