Add --output-location option

## Overview

We need an option to configure the location of `harvest` output.

## Requirements

- Add an option to optionally configure the location of `harvest` results.
- Applicable to `collate` sub-command
- Applicable to `report` sub-command

## Approach

- Update CLI
- Update write functionality for both `collate` and `report`.

## Security and Privacy

N/A

## Test Plan

TBD

Start by locating the CLI definitions for the collate and report subcommands, then trace their existing output-writing paths. Implement the optional output location for both commands and verify that each writes harvest results to the configured location; the issue provides no named tests, so add or run the relevant command-level checks you find.

Written by the indexing model from the issue text.