chore(gatsby-parcel-config): stabilize ts compilation parcel output

[pieh]

Description

Right now, because of parcel-bundler/parcel#5476 (comment) when you have .ts file only in local plugin, but not in the root of the repo the output is "messed up" - compiled files are in unexpected locations which means gatsby can't load proper gatsby-node file.

This PR looks to first add failing test case covering above and in next commit add "workoarund" (by adding customer namer plugin)

[LekoArts]

Do we not want to move this into our monorepo? Also Parcel wants us to use @gatsbyjs scope: https://parceljs.org/plugin-system/authoring-plugins/#naming

[pieh]

Do we not want to move this into our monorepo? Also Parcel wants us to use @gatsbyjs scope: parceljs.org/plugin-system/authoring-plugins/#naming

For now I renamed package to be @gatsbyjs/ scoped and published and adjusted dependencies in this PR. Adding the package itself to monorepo would be follow up ( https://github.com/pieh/parcel-namer-relative-to-cwd is the current repo )