feat: Standalone lite binaries and cross compilation

[bartlomieju]

This commit adds --target and --lite flags to deno compile subcommand.

--target allows to cross-compile binary to different target architectures by
fetching appropriate binary from remote server on first run. All downloaded
binaries are stored in "$DENO_DIR/dl".

--lite allows to use lite version of the runtime (ie. the one that doesn't contain
built-in tooling like formatter or linter).

[lucacasonato]

LGTM - great feature to have. I am somewhat concerned about this root certificate thing, but lets cross that bridge once someone reports it as an issue :-)

[ry]

LGTM!