Wowza plugin installer - Githubissues

Configurables:

--wowza-directory=/path/to/WowzaStreamingEngine
- Default on Linux /usr/local/WowzaStreamingEngine
- Default on Windows /Program Files (x86)/Wowza Media Systems/Wowza Streaming Engine 4.7.7/
- Default on MacOS is /Library/WowzaStreamingEngine
--channel=some-branch — could be master or any other branch name
- Default: latest
--api-key=F5E1D5FE-9238-4517-A4CF-816E983C903A
- Default:
- If they already have an API key in Server.xml, re-use that.
- If they don't already have an API key, prompt the user for one.

Behavior:

Queries the latest version of the JAR file from https://build.livepeer.live/LivepeerWowza/${channel}.json. It will return an object of the form:
```
{
"version": "0.0.1",
"url": "https://build.livepeer.live/LivepeerWowza/0.0.1/LivepeerWowza.jar"
}
```
Downloads the latest version of the JAR file from the provided URL, places it in ${wowza-directory}
Modifies all of the Application.xml files:
- ${wowza-directory}/Application.xml
- Each subdirectory should also have an Application.xml, we want to modify all of them, such as ${wowza-directory}/live/Application.xml and ${wowza-directory}/vod/Application.xml It inserts the LivepeerWowza module into the list of modules located at <Root><Application><Modules>:
```
<Module>
<Name>LivepeerWowza</Name>
<Description>Offloads Wowza transcoding to the Livepeer network</Description>
<Class>org.livepeer.LivepeerWowza.ModuleLivepeerWowza</Class>
</Module>
```
It also modifies ${wowza-directory}/conf/Server.xml to insert ${api-key}

<Property>
  <Name>livepeer.org/api-key</Name>
  <Value>F5E1D5FE-9238-4517-A4CF-816E983C903A</Value>
  <Type>String</Type>
</Property>

All of this should be idempotent, such that the user can re-run the script to download the latest version and it won't re-modify the XML files.

livepeer / livepeer-wowza