Enable caching for plugin binary artifacts

[ramizpolic]

Problem Statement

The downloaded artifacts for binary mode are not cached between runs. It would be useful to allow caching to reduce time needed to setup and perform a scan using plugins.

Proposed Solution

Add two more config options for plugins to allow users to

1. specify custom dir if they want the plugin data to be saved/loaded to allow caching via binary_artifacts_path which would default to ${HOME}/.vmclarity/plugins if not specified
2. specify keep/clean option if they want to preserve artifacts pulled in in a given run via binary_artifacts_keep. Alternatively, binary_artifacts_clean config can be used that defaults to preserve behaviour when not specified.

For example

## reruns preserve new and reuse existing artifacts
binary_artifacts_path: /tmp/plugin-artifacts
binary_artifacts_keep: true
# or binary_artifacts_clean: false

## reruns reuse existing artifacts between runs but do not preserve the new artifacts
binary_artifacts_path: /tmp/plugin-artifacts
binary_artifacts_keep: false
# or binary_artifacts_clean: true

## reruns neither reuse nor preserve
# empty binary_artifact configs
# or binary_artifacts_clean: true