[v5] CommonMediaRequest

[bbert]

This PR integrates the CommonMediaRequest and CommonMediaResponse API from SVTA CommonMediaLibrary, available from version 0.5.0, to make dash.js relying on this reference API to enable applications to intercept requests and responses and to read stats/metrics of all requests.

See issue #4152

Pull request on SVTA Github to include CommonMediaRequest and CommonMediaResponse API : streaming-video-technology-alliance/common-media-library#18

What has been done so far:

• add MediaPlayer API ro register requests and responses interceptors as specified in CommonMediaLibrary
• refactor HTTPLoader, XHRLoader and FetchLoader to rely CommonMediaRequest and CommonMediaResponse
• Apply the request and response interceptors from HTTPLoader
• Add a sample application (in typescript) that adds a request interceptor (to update video segment request url by adding a query parameter) and a response interceptor (to add a response header)

To test the sample:

1. Go to folder samples/network-interceptor
2. Build the project: npm install then npm run build
3. Open file localhost:3000/samples/network-interceptor/index.html (once npm start is running on project)

What remains to be done:

• update/complete the CommonMediaRequest and CommonMediaResponse if needed
• apply the interceptors also on licence requests/responses
• remove the RequestModifier API

! Note:
Npm package @svta/common-media-library declared in package.json does not integrate yet the request package.
To enable building and sample running, you need:

1. to clone@svta/common-media-library
2. checkout branch common-media-request
3. build the project
4. Manually copy the dist files into node_modules/@svta/common-media-library and into samples/network-interceptor/node_modules/@svta/common-media-library