Add image support to hangouts notifications

[quazzie]

Description:

Adds image support to hangouts notification

Related issue (if applicable): fixes #

Pull request in home-assistant.github.io with documentation (if applicable): home-assistant/home-assistant.io#6254

Checklist:

• The code change is tested and works locally.
• Local tests pass with tox. Your PR cannot be merged unless tests pass

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated in home-assistant.github.io

[pvizeli]

Instead to try to validate the url use a schematic like other notify platforms like:

{
   "photo": [
       "file": "...",
       "url": "...",
   ]
}

Or simple:

{
   "image_file": "",
   "image_url": "",
}

You can self select your style, but don't use this urlparse handling.

Examples:

• https://www.home-assistant.io/components/notify/
• https://www.home-assistant.io/components/notify.telegram/

After that it should be ready to merge.

[quazzie]

@pvizeli this ok ?

[pvizeli]

We should create a helper in future

[balloob]

So this PR added incorrect YAML to services.yaml which caused Home Assistant to not boot at all. Which begs the question, did anyone run this PR @quazzie ?

[quazzie]

Hmm :( sorry last commit (rename to image_file/_url) was made with github edit as i was away so no that last commit was not run. Stupid mistake, sorry.