UNSTABLE: new API, yet to be vetted.
Similar to the command line functionality of
deno run or
settings provided. The source code can either be provided or the modules
can be fetched and resolved in line with the behavior of the command line.
allow-net if sources are not provided.
The specifier that will be used as the entry point.
If no sources are provided, then the specifier would
be the same as if you typed it on the command line for
deno run. If sources are provided, it should match
one of the names of the sources.