create `lens init` command to force config file creation

[boojamya]

Currently the the ~/.lens/config.yaml file is created the first time lens needs to query the config. This could be confusing for users first getting setup with Lens.

One option is to have an official lens init command to create the config file instead of it being randomly created the first time lens needs to query it. There may be some other arguments we can add in that init command to streamline the initial config setup.

cc: @prasincs

[prasincs]

I think one use case is to select the chains to initialize with like

lens init --chains osmosis,cosmos...

or if we want to get fancy something interactive to ask