In the passing, rename it to NeonLocalCli, to reflect that the binary
is called 'neon_local'.
Add wrapper for the 'timeline_import' command, eliminating the last
raw call to the raw_cli() function from tests, except for a few in
test_neon_cli.py which are about testing the 'neon_local' iteself. All
the other calls are now made through the strongly-typed wrapper
functions