Add support for npm workspaces

[pombredanne]

See https://docs.npmjs.com/cli/v10/using-npm/workspaces

See also the yarn "nohoist" https://classic.yarnpkg.com/blog/2018/02/15/nohoist/ (not yet in npm npm/rfcs#287 ?)

Some examples:

• https://github.com/renovatebot/renovate/blob/19198355b226a15710d490ca0535041d8b215043/lib/modules/manager/npm/__fixtures__/inputs/workspaces.json#L5 (may be other examples there)
• https://github.com/vanilla/vanilla/blob/5b1704d9e798c3d4d33d22a05ac30cd862d4432d/plugins/rich-editor/package.json#L2
• https://github.com/panodata/grafana/blob/f0b3dc221101d2a8553d504532d556ec6139061b/package.json#L3
• https://github.com/mudita/mudita-center/blob/57c697063e64caae91184b5bc0b7d25bde89fff1/package.json#L6

[pombredanne]

@AyanSinhaMahapatra ping... is this something you started looking at?