Use C-style backslash escaping to sanitize non-UTF-8 strings.
The functions are compatible with glib's g_strcompress() and
g_strescape().
The difference is only that g_strescape() escapes all non-printable,
non ASCII character as well, while nm_utils_str_utf8safe_escape()
-- depending on the flags -- preserves valid UTF-8 sequence except
backslash.
The flags allow to optionally escape ASCII control characters and
all non-ASCII (valid UTF-8) characters. But the option to preserve
valid UTF-8 (non-ASCII) characters verbatim, is what distinguishes
from g_strescape().
(cherry picked from commit df6d27b33a)
The "shared" directory contains files that are possibly used by all components
of NetworkManager repository.
Some of these files are even copied as-is to other projects (VPN plugins, nm-applet)
and used there without modification. Move those files to a separate directory.
By moving them to a common directory, it is clearer that they belong
together. Also, you can easier compare the copied versions to their
original via
$ diff -r ./shared/nm-utils/ /path/to/nm-vpn-plugin/shared/nm-utils/
