Save to JSON

[Firesphere]

Add the ability to save the generated headers to a JSON file.

Current situation

• An engineer has to manually generate a JSON file or array to load the pre-set configuration
• The updates to the configuration (e.g. user custom added domains) can not be saved in the JSON

Wished situation

• Add an API point to export the generated CSP headers, minus calculated hashes, to a JSON or array
• Enabling a much faster loading of the configuration (bypassing most of e.g. database calls)

Additional awesomeness

• Make the loading and exporting time-based. If a change is detected compared to the latest version requested (e.g. latest change in a database), load and update the config afterwards

(I understand additional awesomeness is very project specific)

[paragonie-security]

This is being done in #56 and will land in the next release.