doc: Improve layout of network Kconfig options table

The layout of this table unreasonably assigns narrow widths for
for column(s) with lots of content, and wise-versa.

Define relative column widths to be more in sync with column
content. This will potentially produce more compact table, making
it more readable, clearer and more visually pleasing.

Signed-off-by: Aleksandar Markovic <aleksandar.markovic.sa@gmail.com>

doc/connectivity/networking/api/net_config.rst

diff --git a/doc/connectivity/networking/api/net_config.rst b/doc/connectivity/networking/api/net_config.rst
index 93ee6d2..41dad04 100644
--- a/doc/connectivity/networking/api/net_config.rst
+++ b/doc/connectivity/networking/api/net_config.rst
@@ -19,7 +19,7 @@
 
 .. csv-table:: Kconfig options for network configuration library
    :header: "Option name", "Description"
-   :widths: auto
+   :widths: 45 55
 
    ":kconfig:option:`CONFIG_NET_CONFIG_SETTINGS`", "This option controls whether the
    network system is configured or initialized at all. If not set, then the