fix error when build apigateway on ARM64

[thunderZH963]

I try to build a openwhisk-apigateway image on my arm64 platform(NVDIA Bluefiled2).

But https://github.com/apache/openwhisk-apigateway/issues/396 occurs.

So I try to modify Dockerfile to make it work well on arm64.

Mainly includes, 1.fix 404 link for pcre 2.fix logic in 'adding Openresty, NGINX and PCRE'