JSON format for client-server communication

[lxpdd]

AS IS state

Currently there is a two special cases for getting copybook contents:
copybook-resolve - to handle copybook request
copybook-download - to handle copybook download request

And the format is not reliable, neither extensible because depends on regex rule:
/^([^.]+)\.([^.]+)(\.(quiet|verbose))?\.(.+)\.([^.]+)\.([^.]+)$/
Examples of the plaintext in server->client communication: 
cobol-lsp.copybook-resolve.cobFile.bookName.COBOL
cobol-lsp.copybook-download.quiet.cobFile.bookName2.COBOL

Acceptance Criteria

• No Regexp used for processing client-server messages
• Command to resolve or download copybooks are sent in JSON format

Definition of Done

• The story is implemented according to the description.
• Unit testing done (Preferably by TDD approach, coverage should be at least 70%).
• Code review done by at least one other team member.
• Manual testing is done.
• Documentation is added and reviewed (if needed).
• The pull request is approved.
• The story is merged into the development branch.
• Tests are performed on the development branch.

Technical proposal

Data format should be change format into JSON to be more reliable, readable and extensible,
it could contains such field as:
{prefix, cobolFileName, copybookName, dialect, command}