build: Move reflect-metadata & express from devDependencies to dependencies

[dbartel]

This fixes an issue I ran into while proving out a production-ready environment for hosting a Universal app. I noticed some devDependencies modules are required to be installed in order to run the application, which should not be the case.

Changes in a nutshell: Moves express and reflect-metadata from devDependencies to run dependencies.

Steps to reproduce issue

1. Clone repo, run npm install
2. Build project with npm run build:ssr
3. Remove node_modules
4. Run npm install --production to install run-time modules
5. Run node dist/server

Following these steps, the node server will crash on launch due to missing dependencies:

> node dist/server
    throw err;
    ^
Error: Cannot find module 'reflect-metadata'
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:581:15)
    at Function.Module._load (internal/modules/cjs/loader.js:507:25)
    at Module.require (internal/modules/cjs/loader.js:637:17)
    at require (internal/modules/cjs/helpers.js:20:18)
    at Object.<anonymous> (/home/dbartel/projects/ext/universal-starter/dist/server.js:4:1)
    at Module._compile (internal/modules/cjs/loader.js:689:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:700:10)
    at Module.load (internal/modules/cjs/loader.js:599:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:538:12)
    at Function.Module._load (internal/modules/cjs/loader.js:530:3)

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[dbartel]

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