Reduce the size of Go binaries by stripping and compressing

[wallrj]

• Strip the debugging information (-s -w)
• Compress the binary using upx
• Added more memory to the operator pod so that it has room to self-extract

See: https://blog.filippo.io/shrink-your-go-binaries-with-this-one-weird-trick/

It does slow down the build by a few seconds, but it reduces the sizes quite significantly which helps when doing regular docker-push to GCR.

Not sure it's worth it, but it's been an interesting experiment.

• Original

  docker images
  REPOSITORY                                                       TAG                  IMAGE ID            CREATED             SIZE
  gcr.io/jetstack-richard/etcd-cluster-operator-backup-agent       v0.2.0-8-g1c6a509    d5ea0f5d30d4        16 hours ago        44.1MB
  gcr.io/jetstack-richard/etcd-cluster-operator-proxy              v0.2.0-8-g1c6a509    7007de2e913f        16 hours ago        41.9MB
  gcr.io/jetstack-richard/etcd-cluster-operator-controller-debug   v0.2.0-8-g1c6a509    0c7722c7de4d        16 hours ago        66.6MB
  gcr.io/jetstack-richard/etcd-cluster-operator-controller         v0.2.0-8-g1c6a509    b664775d6d2a        16 hours ago        54.5MB

• -ldflags=-s -w"

  docker images
  REPOSITORY                                                       TAG                  IMAGE ID            CREATED             SIZE
  quay.io/improbable-eng/etcd-cluster-operator-backup-agent        v0.2.0-8-g1c6a509    4dc9c218979d        5 seconds ago       32.9MB
  quay.io/improbable-eng/etcd-cluster-operator-proxy               v0.2.0-8-g1c6a509    d87ffff4789f        9 seconds ago       31.3MB
  quay.io/improbable-eng/etcd-cluster-operator-controller-debug    v0.2.0-8-g1c6a509    0536168ed506        14 seconds ago      52.6MB
  quay.io/improbable-eng/etcd-cluster-operator-controller          v0.2.0-8-g1c6a509    dc8cd289a634        23 seconds ago      40.5MB

• upx

  docker images
  REPOSITORY                                                       TAG                  IMAGE ID            CREATED             SIZE
  quay.io/improbable-eng/etcd-cluster-operator-backup-agent        v0.2.0-8-g1c6a509    3699f1bb8b21        4 seconds ago       10.9MB
  quay.io/improbable-eng/etcd-cluster-operator-proxy               v0.2.0-8-g1c6a509    cb00b8727052        8 seconds ago       10.5MB
  quay.io/improbable-eng/etcd-cluster-operator-controller-debug    v0.2.0-8-g1c6a509    606eccae02fe        13 seconds ago      25.5MB
  quay.io/improbable-eng/etcd-cluster-operator-controller          v0.2.0-8-g1c6a509    81884510a8a7        21 seconds ago      13.4MB

  Stacked on: #164