[Feature] Create 'cosmos_node_client' package

[andrzejchm]

Create new package called cosmos_node_client for communicating with the Cosmos nodes.

Acceptance criteria

• new package structure inside the packages subfolder without any code yet with comsos_lint #package plugged in for static code analysis
• amend the pull-request.yaml file to perform all the necessary checks on the new package

[Zfinix]

Starting work on this today