move our packages to use "@malloy-lang" scope (which we own on npm)

[bporterfield]

There is a concern that perhaps someone would think we have published npm packages (we have not) and if some nefarious actor grabs a package on npm with a name we're using, some other developer might intend to install a malloy package and accidentally install the bad package.

This change resolves that concern by scoping the packages to @malloy-lang/{package-name} - an organization name in npm that we own - with the exception of the VScode extension. VSCode extensions have chosen (possibly poorly?) to utilize package.json as the manifest file for an extension - but they do not support all possible values for the name property and as such do not support scoped names.

While it is not intended to be installed via npm, we have reserved the malloy-vscode name on npm by publishing the vs-code package to it.

[christopherswenson]

Looks great 👍