Feature support alpine stretch, reduce nacos-server image size

[fdiskbrain]

Purpose

• Reduce nacos-server docker image size
• Support more arch without change main docker image

Support alpine

• Add Dockerfile-alpine
• Add package bash
• Remove ENV JAVA_HOME JAVA from dockerfile
• Refine Docker file reduce layer

Support stretch

• Add Dcokerfile-stretch
• Remove ENV JAVA_HOME JAVA from dockerfile
• Refine Docker file reduce layer

Startup scripts modify

• Alpine/stretch image ENV JAVA_HOME provider by base image. java bin is in system PATH.
• Add ${java} default value java to build/bin/docker-startup.sh,

Testing

• build image at dockerhub
  Docker hub images
• Test run standalone mode in local

[CLAassistant]

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1 out of 2 committers have signed the CLA.

✅ fdiskbrain
❌ Rong zhu(FB)

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