Suggestion: Remove @semantic-release/npm as direct dependency

[pataar]

New feature motivation

As someone, and I won't be the only one, that doesn't use the @semantic-release/npm plugin, it adds a lot of extra dependencies. Especially because of the npm dependency of @semantic-release/npm. My request would be to make it optional to install it as plugin.

New feature implementation

Remove @semantic-release/npm as direct dependency. Update the documentation to instruct to install it separately when needed.

[gr2m]

We plan to release @semantic-release/core which won't include any plugins, so people will be able to build their own semantic-release version for different use cases.

I cannot give you an ETA on it though, we don't have much time to work on semantic-release right now, and we want to finish the transition to ESM before taking on anything else

[pataar]

That sounds like a great solution