Add site support for motortrendondemand.com

Please follow the guide below

You will be asked some questions and requested to provide some information, please read them carefully and answer honestly
Put an x into all the boxes [ ] relevant to your issue (like this: [x])
Use the Preview tab to see what your issue will actually look like

Make sure you are using the latest version: run `youtube-dl --version` and ensure your version is 2018.04.16. If it's not, read this FAQ entry and update. Issues with outdated version will be rejected.

[x] I've verified and I assure that I'm running youtube-dl 2018.04.16

Before submitting an issue make sure you have:

[x] At least skimmed through the README, most notably the FAQ and BUGS sections
[x] Searched the bugtracker for similar issues including closed ones
[x] Checked that provided video/audio/playlist URLs (if any) are alive and playable in a browser

What is the purpose of your issue?

[ ] Bug report (encountered problems with youtube-dl)
[x] Site support request (request for adding support for a new site)
[ ] Feature request (request for a new functionality)
[ ] Question
[ ] Other

The following sections concretize particular purposed issues, you can erase any section (the contents between triple ---) not applicable to your issue

If the purpose of this issue is a bug report, site support request or you are not completely sure provide the full verbose output as follows:

Add the -v flag to your command line you run youtube-dl with (youtube-dl -v <your command line>), copy the whole output and insert it here. It should look similar to one below (replace it with your log inserted between triple ```):

[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: ['-v', 'https://www.motortrendondemand.com/detail/el-paso-to-la-the-hard-way/0_dmio874f/']
[debug] Encodings: locale cp1252, fs mbcs, out cp850, pref cp1252
[debug] youtube-dl version 2018.04.16
[debug] Python version 3.4.4 (CPython) - Windows-10-10.0.16299
[debug] exe versions: ffmpeg N-77045-ga16243a, ffprobe N-77045-ga16243a
[debug] Proxy map: {}
[generic] 0_dmio874f: Requesting header
WARNING: Falling back on generic information extractor.
[generic] 0_dmio874f: Downloading webpage
[generic] 0_dmio874f: Extracting information
ERROR: Unsupported URL: https://www.motortrendondemand.com/detail/el-paso-to-la-the-hard-way/0_dmio874f/
Traceback (most recent call last):
  File "C:\Users\dst\AppData\Roaming\Build archive\youtube-dl\rg3\tmp9r95p1_v\build\youtube_dl\YoutubeDL.py", line 789, in extract_info
  File "C:\Users\dst\AppData\Roaming\Build archive\youtube-dl\rg3\tmp9r95p1_v\build\youtube_dl\extractor\common.py", line 440, in extract
  File "C:\Users\dst\AppData\Roaming\Build archive\youtube-dl\rg3\tmp9r95p1_v\build\youtube_dl\extractor\generic.py", line 3166, in _real_extract
youtube_dl.utils.UnsupportedError: Unsupported URL: https://www.motortrendondemand.com/detail/el-paso-to-la-the-hard-way/0_dmio874f/

If the purpose of this issue is a site support request please provide all kinds of example URLs support for which should be included (replace following example URLs by yours):

Single video: https://www.motortrendondemand.com/detail/el-paso-to-la-the-hard-way/0_dmio874f/
Another single video: https://www.motortrendondemand.com/detail/700-horsepower-2-400-miles-crusher-camaro-engine-swap-aftermath/0_zn84jd9j/

Note that youtube-dl does not support sites dedicated to copyright infringement. In order for site support request to be accepted all provided example URLs should not violate any copyrights.

Description of your issue, suggested solution and other information

The site uses Kaltura to stream the video but the Kaltura extractor doesn't seem to recognize/support it. This results in ERROR: Unsupported URL. This could be fixed by either modifying the existing Kaltura extractor (I think) or by creating a new one specifically for this site. The generic extractor seems to be able to download the video if a direct m3u8 link is passed (inspect element -> network tab -> set a.m3u8 as filter and copy URL). The recent commit e30991f9206f98605ba6c4880ed40ad5556fa0b8 did not address this issue either.

Note: The site likes to prompt users who use adblocking software to login/create an account, pausing or whitelisting the site should get past it.

ytdl-org / youtube-dl