Move build.sh into the sdk binary

[AlexNPavel]

The build.sh script is mostly unnecessary and does not provide any benefits over handing the building from the operator-sdk's binary. In addition, any updates that the sdk gets will not be reflected in existing project as build.sh is generated on new. Currently, this will cause issues for people created a project before the --enable-tests flag was added to the sdk and then try to use --enable-tests.

In addition, we should look into the way that dockerfiles are managed in cases like this. Currently, the above situation (trying to build an image with tests on a project that was generated before that was supported) will not work even with the build script merge because it will be missing the test-framework dockerfile. For now, we can just check if it exists and generate it if it doesn't, but in the long-term, we should find a better solution for managing these files.

[hasbro17]

Elaborating on the current issue.
Before #469 operator-sdk build would run the build script tmp/build/build.sh

#!/usr/bin/env bash

set -o errexit
set -o nounset
set -o pipefail

if ! which go > /dev/null; then
	echo "golang needs to be installed"
	exit 1
fi

BIN_DIR="$(pwd)/tmp/_output/bin"
mkdir -p ${BIN_DIR}
PROJECT_NAME="memcached-operator"
REPO_PATH="github.com/operator-framework/operator-sdk-samples/memcached-operator"
BUILD_PATH="${REPO_PATH}/cmd/${PROJECT_NAME}"
echo "building "${PROJECT_NAME}"..."
GOOS=linux GOARCH=amd64 CGO_ENABLED=0 go build -o ${BIN_DIR}/${PROJECT_NAME} $BUILD_PATH

But now with operator-sdk build --enable-tests it expects the script to build the test binary as well:

#!/usr/bin/env bash

set -o errexit
set -o nounset
set -o pipefail

if ! which go > /dev/null; then
	echo "golang needs to be installed"
	exit 1
fi

BIN_DIR="$(pwd)/tmp/_output/bin"
mkdir -p ${BIN_DIR}
PROJECT_NAME="memcached-operator"
REPO_PATH="github.com/operator-framework/operator-sdk-samples/memcached-operator"
TEST_PATH="${REPO_PATH}/${TEST_LOCATION}"
BUILD_PATH="${REPO_PATH}/cmd/${PROJECT_NAME}"
echo "building "${PROJECT_NAME}"..."
GOOS=linux GOARCH=amd64 CGO_ENABLED=0 go build -o ${BIN_DIR}/${PROJECT_NAME} $BUILD_PATH
if $ENABLE_TESTS ; then
	echo "building "${PROJECT_NAME}-test"..."
	GOOS=linux GOARCH=amd64 CGO_ENABLED=0 go test -c -o ${BIN_DIR}/${PROJECT_NAME}-test $TEST_PATH
fi

So for projects with the older script the operator-sdk build --enable-test command will fail. So we should stop generating helper scripts and just implement them as Go code in the binary.

I've already done the same for the codegen script tmp/codegen/update-generated.sh in the controller-runtime refactor branch.
5eb5814