Allow container source image to be configured

[jwerle]

No description provided.

[mikeseese]

Hi @jwerle, what's the use case for this change? Can you please provide more details? I'm not seeing a reason jumping out to support merging

[jwerle]

One use case for us is allowing us to specify options like the server where an image lives. The work around for now is to use the client.request() method manually

[mikeseese]

In addition to the other comment/suggestion, the typing of image needs to be updated in the function definition of both createContainer and launchContainer. See https://github.com/trufflesuite/ts-lxd/pull/4/files#diff-d554f9108d9df7d1caac4ea44d302504R231 and https://github.com/trufflesuite/ts-lxd/pull/4/files#diff-d554f9108d9df7d1caac4ea44d302504R235

This type should be something like image: string | IImageDefinition where IImageDefinition is an interface I'd like for you to define and it should reflect the available options at https://github.com/lxc/lxd/blob/master/doc/rest-api.md#post-optional-targetmember. It can be placed near the top around line 32.