Create a new clients/ subdirectory at the top level, and move cli/ and
tui/ into it, as well as nm-online.c (which was previously in test/,
which made no sense).
cli/ was split into two subdirectories, src/ and completion/. While
this does simplify things (given that the completion file and the
binary both need to be named "nmcli"), it bloats the source tree, and
we can work around it by just renaming the completion file at install
time. Then we can combine the two directories into one and just have
it all under clients/cli/.
Remove all remaining GParamSpec name and blurb strings (and fix
indentation while we're there), and add G_PARAM_STATIC_STRINGS to all
paramspecs that were lacking it.
Make all the signals RUN_FIRST instead of RUN_LAST. In particular,
this fixes a crash when creating a new connection and activating the
listbox directly, in which case nmt_newt_listbox_activated() was
running after NmtAddConnection:create_connection() had already quit
the form and unrealized the listbox.
