Upgrade SPS frontend + example to PSInfra 5.5 and functionality to set SS in url parameters.

[lukehb]

Relevant components:

• Scalable Pixel Streaming Frontend library
• Examples
• Docs

Problem statement:

SPS frontend was using PSInfra 5.4 so it was not on the latest code.

Additionally, there was no way to specify a signalling server url via url parameters.

Solution

• Upgrades frontend and example to use PSInfra 5.5, bumps relevant versions and changes relevant types.
• Changes the enforceSpecialSignallingServerUrl to handle reading the url parameter if it is set, otherwise fallback to constructing the signalling url as before.

Documentation

N/A

Test Plan and Compatibility

• Test SPS streaming using locally built frontend and supplying url parameters for signalling server url - streaming works.
• Verified if URL is not specified then it will attempt to construct it.
  - Note: I have not tested using a live deployment of SPS (say on CW) where the signalling url is built using the actual url.

[lukehb]

I recommend reviewing using: https://github.com/ScalablePixelStreaming/Frontend/pull/56/files?diff=split&w=1

As some whitespace seems to have been messed up.

[dan-tw]

Tested on CW/AWS/Local

• Automated SS building worked as per normal
• Supplying a SS URL via params works (was able to stream an instance on CW from AWS frontend using CW SS URL)

Lgtm!