Create Go Single VM Mycelium Script

[Mik-TF]

Situation

• As part of the task to put Mycelium at the forefront of the TF documentation and ecosystem (see this issue on info_grid: add mycelium support in all of the docs info_grid#617), we want to add some info on Mycelium for tfgrid-sdk-go
• In tfgrid-sdk-ts, we have one script to deploy a single VM with mycelium: https://github.com/threefoldtech/tfgrid-sdk-ts/blob/development/packages/grid_client/scripts/single_vm_mycelium.ts
• We propose to add something equivalent for tfgrid-sdk-go in script: https://github.com/threefoldtech/tfgrid-sdk-go/tree/development/grid-client/scripts

TODO

• Add script in tfgrid-sdk-go grid-client to deploy a single VM on the grid with Mycelium

@xmonader if this is redundant or that it's already implied in this: https://manual.grid.tf/documentation/developers/go/grid3_go_vm.html, we can simply add this example in the tfgrid-sdk-go repo, or else if you have another idea. Thanks