Fix picards location issue for singulairty

[JonKeatley112]

Add the changes made to the Picard Dockerfile by @gbggrant to resolve the location issue when using a singularity container.

Picard was stored by default in /root but because singularity executes with the user's credentials it is impossible to access unless executed as root. The change proposed by @gbggrant is to move the jar from /root to /bin