common connection string kvs

In the previous discussions for connection strings, we discussed unifying the possible options that can be passed with a connection string w.r.t. their names and default values. We should finish that discussion and merge it to be part of the connection-string RFC document.

Start by locating the connection-string RFC document and reviewing the previous discussions referenced in the issue. Identify the agreed option names and default values, then determine how that discussion should be incorporated into the RFC; the work is done when the unified options and defaults are documented.

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