Implement object package manager based on samp-objects.com

[Southclaws]

Since 0.3.8 is coming and I'm already working on a directory site for sharing objects, it makes sense to add version control and auto-acquisition capabilities for objects too!

Since usernames and object names use the same pattern as GitHub, the patterns would be the same as code dependencies.

Proposed usage in samp.json:

{
    "gamemodes": [ "grandlarceny"],
    "plugins": "streamer",
    "objects": [
        "Southclaws/barrel",
        "samp-objects.com/J0shES/Kyle-Smith-Skin",
        "https://samp-objects.com/TommyB/SomeRoleplayNonsense"
    ]
}

Of course a server could use thousands of objects, so it would make sense to store this in a separate file, aptly named objects.json:

[
    "Southclaws/barrel",
    "samp-objects.com/J0shES/Kyle-Smith-Skin",
    "https://samp-objects.com/TommyB/SomeRoleplayNonsense"
]

Of course the actual syntax would need to specify the other parameters of AddCharModel and AddSimpleModel so they would likely be JSON objects instead of strings - however, it could be handy to define it all in a single string...

I'd love to have some feedback on this from people who have had a chance to play with the new system - ideally on some of the pitfalls or errors you have encountered that could get caught by sampctl and provide better error messages.