ApplyCmd: Build, return, and store execution report

[azriel91]

Enables communication of what happened for a given execution.

Also enables historical lookup.

May include:

• Beginning params specs, params, state.
• Goal params specs, params, state.
• Timestamps, duration.
• Errors -- all must be serializable. Likely include Clone, PartialEq, Eq bounds so we treat all errors as values.

Consider the ability to merge multiple reports into one report -- a user may invoke, cancel, fix, and invoke commands repeatedly; yet one report that captures that grouping of invocations is more digestable than many small reports.