Adjust configuration options

[tmaiaroto]

Allow a configuration's options (if any) to be adjusted after the configuration is created.

This is particularly useful for DynamoDB. A configuration can be created with a certain value for read and write capacity units, but then later need an increase to scale for usage.

This can be done using AWS' console of course...But that's not real convenient and maybe the credentials being used only allow access to DynamoDB - no console login. So it's super handy to be able to adjust any settings for a configuration through discfg.

When more storage options are added, like S3, then different options may be available. Though I can't see all too many being needed. I can't think of anything S3 would need... Well, maybe it can turn on/off reading from a public URL. Who knows.

Config the config =) Gotta happen.

[tmaiaroto]

This is mostly done. Just needs a refactor. The original thinking was all based around how the API would work. A simple HTTP OPTIONS request that would be both a getter and a setter. If there was a JSON body passed, then parse that and update the configuration storage options. Otherwise, just read the configuration info - which would include information about the configuration storage options.

Though it works differently from the CLI. There's less info returned to the command line for starters. Also, it doesn't make sense to have one command with an optional argument that changes the behavior of the command. There's an cfg info (also available as just info for convenience) command as well as an cfg update. So it doesn't make sense to lump the getter and setter into one function.