Add --no-owns CLI flag for dependencies command

[regexident]

This option filters out structural edges, as well as any nodes with a degree of 0 (i.e. disconnected nodes).

Fixes #274

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Without --no-owns

cargo run --release -- dependencies --manifest-path "tests/projects/smoke"  > ./graph-without-owns.dot

With --no-owns

cargo run --release -- dependencies --manifest-path "tests/projects/smoke" -
-no-owns > ./graph-without-owns.dot

[wduminy]

I think this feature works well. I attached the two images below.

Notice some blocks does not show in the second image which helps to create the view I wanted.
Thanks!

Args to produce image:

cargo-modules dependencies -p rc-bot --no-externs --no-owns --no-types --no-traits --no-fns | dot -Tsvg -ono-owns.svg

With owns:

Without owns

[regexident]

I think this feature works well.

Cool! I guess I'll leave this open until next week's release (Tuesday/Wednesday-ish) then and merge it if no major concerns with the implementations have come up by then.