new: add host as a key in get_product_name

[vincentullmann]

Changelog Description

added {host} as a key to be available in get_product_name

Additional info

It felt strange beeing able to filter profiles by host, but then to not be able to have host as an option in the template itself.
In our case it lead to the creation of multiple profiles for each host:

[
    {
      "product_base_types": ["workfile"],
      "host_names": ["nuke"],
      "template": "{product[type]}{Task[name]}Nuke"
    },
    {
      "product_base_types": ["workfile"],
      "host_names": ["houdini"],
      "template": "{product[type]}{Task[name]}Houdini"
    },
    {
      "product_base_types": ["workfile"],
      "host_names": ["maya"],
      "template": "{product[type]}{Task[name]}Maya"
    },
    {
      "product_base_types": ["workfile"],
      "host_names": ["substancepainter"],
      "template": "{product[type]}{Task[name]}SubstancePainter"
    },
    {
      "product_base_types": ["workfile"],
      "host_names": ["zbrush"],
      "template": "{product[type]}{Task[name]}ZBrush"
    }
  ]

With this change this can be consolidated into a single profile:

[
    {
      "product_base_types": ["workfile"],
      "host_names": [],
      "template": "{product[type]}{Task[name]}{Host[name]}"
    }
]

str vs. dict

I wasn't 100% sure weather use the string {host} or dict {host[name]} variant

I'e went with the dict version as it feels more in line with how the product and task entities are represented and keeps the door open for other attributes in the future. ({host[label]} or similar in the future for SubstancePainter or ZBrush)

{host} is nice and short and does the job perfectly well right now, but i'm worried we end up having to implement a similar check as the {task} -> {task[name]} conversion to migrate templates if we ever decide to change it

Testing notes:

1. add {host[name]} or {Host[name]} to a product name template
2. confirm in the creator or any other tool that the host name is added

[iLLiCiTiT]

@moonyuet or @LiborBatek could you try it out? I think it should work.

[moonyuet]

It shows the host name as expected

[LiborBatek]

I have tested it while using it for the workfile product and in blender host app and all been working correctly. I have also inspected the resulting products and whether they are correctly integrated and all seem to be working...

LGTM