feat: Create spot pod by adding bidPerGpu argument

[raghuveer-s]

Create Spot Pod

The create command can only create on-demand pods at the moment since it uses podFindAndDeployOnDemand in the GraphQL API underneath. If we want to create spot pods, we need to use the podRentInterruptable mutation which needs the bidPerGpu field as part of its input.

How I tested it

Manually tested and verified with the RunPod dashboard as well.
There are a few cases to watch for:

• If bidPerGpu flag does not exist, then use the on-demand pod creation flow.
• If bidPerGpu flag exists and it is <= 0, then return an error.
• If bidPerGpu flag exists and it is > 0, then attempt to create a spot pod using the GraphQL API.

[raghuveer-s]

Related issue: #11

[justinwlin]

Thanks! Sorry for getting back after so long, Im currently in the process to own this repository and help get things moved in. Ill be looking deeper into this coming week or so, to see what I can do to get this merged in.

[TimPietruskyRunPod]

Closing — this PR adds spot pod support to the old legacy create pod command (cmd/pod/createPod.go), which is deprecated in v2.0.0. The new pod create command (cmd/pod/create.go) needs its own implementation. Created #236 to track adding --bid-per-gpu to the new CLI. Thanks for the contribution — the approach in this PR is a useful reference!