Add code style configurations

This adds a clang-format with the new code style for OpenVPN 3.

A very light Emacs dir-locals configuration has also been added, but
that will most likely not cover all the formatting aspects which
clang-format does.  Running clang-format before committing is still
highly recommended to ensure the coding style is consistent.

Signed-off-by: David Sommerseth <davids@openvpn.net>

.clang-format

@@ -0,0 +1,6 @@
+BasedOnStyle: Microsoft
+ColumnLimit: 0
+SortIncludes: Never
+BreakBeforeBinaryOperators: All
+BinPackArguments: False
+BinPackParameters: False

.dir-locals.el-example

@@ -0,0 +1,10 @@
+; Adapted from https://www.emacswiki.org/emacs/IndentingC
+
+((c++-mode
+  (c-file-style . "stroustrup")
+  (innamespace . -)
+  (inline-open . 0)
+  (inher-cont . c-lineup-multi-inher)
+  (arglist-cont-nonempty . +)
+  (template-args-cont . +))
+)