conf(bat): configure bat defaults + theme

Using `ansi` theme by default as it has can adjust to dark or light base
color scheme transparently, without having to script anything.

Context sharkdp/bat#1746.

private_dot_config/private_bat/private_config

@@ -0,0 +1,27 @@
+# This is `bat`s configuration file. Each line either contains a comment or
+# a command-line option that you want to pass to `bat` by default. You can
+# run `bat --help` to get a list of all possible configuration options.
+
+# Specify desired highlighting theme (e.g. "TwoDark"). Run `bat --list-themes`
+# for a list of all available themes
+#--theme="OneHalfLight"
+#--theme="OneHalfDark"
+--theme="ansi"
+
+# Enable this to use italic text on the terminal. This is not supported on all
+# terminal emulators (like tmux, by default):
+#--italic-text=always
+
+# Uncomment the following line to disable automatic paging:
+#--paging=never
+
+# Uncomment the following line if you are using less version >= 551 and want to
+# enable mouse scrolling support in `bat` when running inside tmux. This might
+# disable text selection, unless you press shift.
+#--pager="less --RAW-CONTROL-CHARS --quit-if-one-screen --mouse"
+
+# Syntax mappings: map a certain filename pattern to a language.
+#   Example 1: use the C++ syntax for Arduino .ino files
+#   Example 2: Use ".gitignore"-style highlighting for ".ignore" files
+#--map-syntax "*.ino:C++"
+#--map-syntax ".ignore:Git Ignore"