Factor out common CMake invocations into functions

As pointed out in https://github.com/apache/arrow-nanoarrow/pull/719#pullrequestreview-2679508541 , in the changes leading up to our nice CMake build + install setup, we've accumulated quite a bit of repetition in CMakeLists.txt. If possible, we should extract out `add_nanoarrow_library()` and/or `add_nanoarrow_test()`.

I seem to remember the last time I tried this that the bundling and IPC dependencies made it hard to factor out but ADBC has nice versions of both of these that seem to allow quite a bit of flexibility.

Start by reviewing the repeated CMake invocations in CMakeLists.txt and the discussion in pull request 719. Compare the flexible ADBC versions of add_nanoarrow_library() and add_nanoarrow_test(), then check how bundling and IPC dependencies affect the extraction. Done means the common setup is factored into reusable functions without breaking those dependency configurations.

Written by the indexing model from the issue text.