fix: refactor arg separator strategy

[cdaringe]

Problem

See #1477, supersedes #1493

Solution

• port arg detection into the packagemanager abstraction
• add version tracking into the struct, as arg separator is often contingent on version
• port CLI version reading into a shared impl for all package managers

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[cdaringe]

hey @nathanhammond, it's been a few weeks. were you able to take a peek yet?

[gaspar09]

Thanks @cdaringe will take a look.

[flex-jonghyen]

Any progress?

[chris-olszewski]

@cdaringe Is this PR still needed after #1612?

[nathanhammond]

Closing this as it is believed addressed by #1612