chore: create private modules, and drop unnecessary modules#1841

Kludex wants to merge 2 commits intodrop-streamablehttp-clientmodelcontextprotocol/python-sdk:drop-streamablehttp-clientfrom

move-to-private-and-drop-duplicated-utilsmodelcontextprotocol/python-sdk:move-to-private-and-drop-duplicated-utilsCopy head branch name to clipboard