Refactor duplicated code across Docker entrypoints

[rdimaio]

There's some code that is duplicated in multiple entrypoints, e.g. the patching logic is the same in these locations:

• containers/daemons/start-daemon.sh

  Line 35 in 7c45913

  if [ -d "/patch" ]

• containers/server/docker-entrypoint.sh

  Line 46 in 7c45913

  if [ -d "/patch" ]

• containers/webui/docker-entrypoint.sh

  Line 43 in 7c45913

  if [ -d "/patch" ]

We could refactor the patching logic into a separate script/function that is called in the entrypoints.