Add encryption to build task CF Task params

[apburnes]

Based on the work in https://github.com/cloud-gov/pages-core/issues/4464

When starting a build task, encrypt the CF Task params and decrypt them in the CF Task app when it runs.

Acceptance Criteria

• [x] Add encryptor to the CF Tasks params
• [x] Add decrypt to the build-task container
• [x] Share and add encryption user provided service to the build tasks space