Use version numbering in Webrtcomm library

[atsakiridis]

Right now, a user only has the Olympus version as a lead in the SIP 'User-Agent' string:

User-Agent: TelScale RTM Olympus/1.0.0

We should automate the generation of an auto-increasing version number in CI/CD and make sure we can easily see it in the JS logs or SIP requests (ideally the User-Agent should show both Olympus + SDK version)

[atsakiridis]

After discussion with @gvagenas we decided to have the User-Agent string configurable. And if not set show the following info:

• Browser version (and name)
• Olympus version
• SDK version

For example:
User-Agent: Chrome 49.0.2623.87 (64-bit), TelScale RTM Olympus/1.0.0, Webrtcomm 1.0.0

[atsakiridis]

First part broken down into: #91, once that is done and we have clear picture we can open another one to automate incrementing