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GH-34865: [C++][Java][Flight RPC] Add Session management messages (#34817)



### Rationale for this change

Flight presently contains no formal mechanism for managing connection/query configuration options; instead, request headers and/or non-query SQL statements are often used in lieu, with unnecessary overhead and poor failure handling.  A stateless (from Flight's perspective) Flight format extension is desirable to close this gap for server implementations that use/want connection state/context.

### What changes are included in this PR?

"Session" set/get/close Actions and server-side helper middleware.

### Are these changes tested?

Integration tests (C++ currently broken due to middleware-related framework issue) and some complex-case unit testing are included.

### Are there any user-facing changes?

Non-breaking extensions to wire format and corresponding client/server Flight RPC API extensions.

* Closes: #34865

Lead-authored-by: Paul Nienaber <paul.nienaber@dremio.com>
Co-authored-by: Paul Nienaber <github@phox.ca>
Co-authored-by: James Duong <jduong@dremio.com>
Co-authored-by: Sutou Kouhei <kou@cozmixng.org>
Signed-off-by: David Li <li.davidm96@gmail.com>