Fix code duplicates in pkg/controllers

There is a lot of copied&pasted code in pkg/controllers, for example in SetupReconciler, NewDaemonSet, UpdateDaemonSet, UpdateStatus, setInitContainer, addVolumeIfMissing functions.

[dupl](https://github.com/mibk/dupl) reports quite a bit of duplicates for this code:
```
pkg/controllers (test) $ dupl -t 50
found 2 clones:
dsa/controller.go:129,159
dsa/controller_test.go:158,188
found 6 clones:
dlb/controller.go:42,53
dsa/controller.go:46,57
fpga/controller.go:44,55
gpu/controller.go:49,60
qat/controller.go:44,55
sgx/controller.go:46,57
found 2 clones:
dlb/controller_test.go:101,126
gpu/controller_test.go:114,139
found 2 clones:
dlb/controller.go:65,84
fpga/controller.go:67,85
found 2 clones:
reconciler.go:363,381
reconciler.go:383,401
found 3 clones:
reconciler.go:233,251
reconciler.go:253,271
reconciler.go:273,291
found 2 clones:
gpu/controller.go:171,207
sgx/controller.go:78,114
found 2 clones:
qat/controller_test.go:127,137
sgx/controller_test.go:161,171
found 2 clones:
reconciler.go:451,463
reconciler.go:465,477
found 6 clones:
dlb/controller.go:108,137
dsa/controller.go:191,220
fpga/controller.go:114,143
gpu/controller.go:282,311
qat/controller.go:120,149
sgx/controller.go:172,201
found 6 clones:
dlb/controller.go:65,72
dsa/controller.go:69,76
fpga/controller.go:67,74
gpu/controller.go:71,78
qat/controller.go:67,74
sgx/controller.go:69,76
found 2 clones:
dlb/controller_test.go:136,146
dsa/controller_test.go:195,205

Found total 12 clone groups.
```

It makes sense to look if we can do better than just copying the same code around.