Model active server capabilities

[Tobiky]

Currently only client capabilities are modeled (and verified through pydantic). The server capabilities should also be modeled, however they do not need to be verified since they are created on the server side. The server capabilities modeled should go into same module, though may be inside a independent sub-module, as the client capabilities. Only the currently active server capabilities need modeling.

The models, or classes, need to be written with Python convention but be convert-able to LSP convention, for example snake case to camel case.

Blocked by:

• Implement textDocument/didOpen notification handling #16
• Implement textDocument/didChange notification handling #17
• Implement textDocument/didClose notification handling #18
• Implement textDocument/publishDiagnostics notification #19
• Implement textDocument/hover request #20
• Implement textDocument/definition request #21
• Implement textDocument/completion request #22