build: add support for custom CSP in webpack devServer

[SuperITMan]

I'm submitting a...

[ ] Regression (a behavior that used to work and stopped working in a new release)
[ ] Bug report  
[X] Feature request
[ ] Documentation issue or request
[ ] Support request => Please do not submit support request here, instead see https://github.com/NationalBankBelgium/stark/blob/master/CONTRIBUTING.md#got-a-question-or-problem

Current behavior

As a user of stark-build, the developer can only edit the following CSP in the local dev server when executing ng serve:

• connect-src
• font-src
• form-action

Expected behavior

Related to #70

The developer should be able to edit all the CSP in the dev server:

• base-uri
• child-src
• connect-src
• default-src
• font-src
• form-action
• frame-src
• frame-ancestors
• img-src
• manifest-src
• media-src
• object-src
• sandbox
• script-src
• script-src-attr
• script-src-elem
• style-src
• style-src-attr
• style-src-elem
• worker-src

And the default values for these CSP should be configured in stark-build.

Environment

Angular version: 7.x
Stark version: 10.x


Others: