Add FIPS build of ADP and bundled ADP/Agent image.

[tobz]

As part of eventually meshing with the Datadog Agent, we need to produce a FIPS-compliant build of ADP as well as a FIPS-compliant ADP-bundled Agent image.

This would involve a new build step that enables the fips feature flag when building ADP, and then another build step for building the converged image using new FIPS-compliant ADP binary. One complication with building the converged image is that there is not yet a public image tag for the Agent to get the FIPS-compliant Agent stuff.

[tobz]

As of #509, we're at least generating FIPS-compliant ADP builds (build-adp-image-fips CI job) but we're still waiting on the generation of public FIPS-compliant Agent container images before we can generate FIPS-compliant ADP-bundled images.