Allow failure for container scanning - INPLATFORM-441

See merge request !37

Sometimes the container scanning step fails because the container scanning runner fails, such as when it runs out of disk space. Instead of making this block the whole build, I think we should allow this step to fail.

Create placeholder tableau executables - INPLATFORM-441

See merge request !36

Only scan image when changes occurred

See merge request !35

Don't volume mount the whole agentcore directory - INPLLATFORM-448

See merge request !34

Secure agent image tag-INPLATFORM-388

See merge request !33

container scanning-INPLATFORM-306