Include Bash, CF and Bosh CLI in docker images used by CF APP support

[gberche-orange]

Is your feature request related to a problem? Please describe.

• As a paas-templates author
• in order to use bosh interpolation in COA managed CF app
• I need the Bosh CLI to be available in the binaries in Docker images used by pre-cf-push.sh and post-deploy.sh hooks

Describe alternatives you've considered

Currently, CF apps such use the following workaround:

coab-depls/common-broker-scripts/pre-cf-push.sh:

BOSH_CLI_VERSION="3.0.1"

#--- Install bosh cli
printf "%bInstall bosh cli \"${BOSH_CLI_VERSION}\"...%b\n" "${YELLOW}" "${STD}"
curl "https://s3.amazonaws.com/bosh-cli-artifacts/bosh-cli-${BOSH_CLI_VERSION}-linux-amd64" -L -s -o /usr/local/bin/bosh
if [ $? != 0 ] ; then
	printf "\n%bERROR: Install bosh cli failed%b\n\n" "${RED}" "${STD}" ; exit 0
fi
chmod 755 /usr/local/bin/bosh

coab-depls/common-broker-scripts/post-deploy.sh:

# Load bash to benefit from standard portable bash syntax
apk add --update bash && rm -rf /var/cache/apk/*

coab-depls/common-broker-scripts/setUpSmokeTestEnv.bash

#--- Parameters
BOSH_CLI_VERSION="3.0.1"

#--- Install bosh cli
printf "%bInstall bosh cli \"${BOSH_CLI_VERSION}\"...%b\n" "${YELLOW}" "${STD}"
curl "https://s3.amazonaws.com/bosh-cli-artifacts/bosh-cli-${BOSH_CLI_VERSION}-linux-amd64" -L -s -o /usr/local/bin/bosh
if [ $? != 0 ] ; then
	printf "\n%bERROR: Install bosh cli failed%b\n\n" "${RED}" "${STD}" ; exit 0
fi
chmod 755 /usr/local/bin/bosh

# Install missing tools
apk add --quiet --no-cache  --repository http://dl-cdn.alpinelinux.org/alpine/edge/testing cloudfoundry-cli

[o-orand]

We may consider usage of Kpack