Add the ability to update stack metadata

[sanderson]

Proposal:
Add the ability to update stack metadata such as name and description. Something like:

influx stacks update --stack-id=xxxxx -n stack-name -d 'stack description'

Current behavior:
Currently you can only add a name and description when manually initializing a stack. There's no way to update them after a stack is created.

Desired behavior:
The ability to update stack metadata.

Use case:

• Providing a name and description for an auto-initialized stack
• Correcting mistakes in a stack name or description

[jsteenb2]

ohhh gimme gimme. This is the last missing bits for stacks 👍