Add npx edgedb binary command that forwards commands to EdgeDB CLI and installs the CLI if it's missing

[scotttrinh]

The workflow for a brand new user who is just checking out EdgeDB for the first time is:

$ npx edgedb project init

Which will prompt that to download the latest version of edgedb, forward the project init command/subcommand to the driver/src/cli.ts module which will detect if the edgedb command exists in the PATH already, and if not, it will install using the curl | sh command. Once it has installed the CLI, it will then invoke the command/subcommand directly on the installed CLI. If the CLI is already installed, it will simply forward the command directly to the CLI.

That means users can use npx edgedb any time they need to run the CLI and it will just always work.