cmd/go-module-query: prototype utility for analysing Go modules
cmd/go-module-query: prototype utility for analysing Go modules

Right now, go-module-query just incrementally processes
index.golang.org/index, fetching go.mod files for all known modules.

In the future, it will allow answering queries on the module graph.

dominikh/go-tools,dominikh/go-tools,dominikh/go-tools,dominikh/go-tools