docs: theme config and list of theme templates (#116)

- Added theme configuration guide in README
- Added some theme templates
- Added list of theme templates in `themes/`

themes/catppuccin-latte.toml

@@ -0,0 +1,19 @@
+border = "#eff1f5"
+accent = "#179299"
+muted = "#9ca0b0"
+text = "#cdd6f4"
+text_sel = "#4c4f69"
+key = "#dc8a78"
+match = "#179299"
+desc = "#a6adc8"
+desc_sel = "#4c4f69"
+sel_bg = "#ccd0da"
+sel_text = "#eff1f5"
+scroll_info = "#dc8a78"
+ghost_text = "#9ca0b0"
+sys = "#24273a"
+sys_sel = "#fe640b"
+hist = "#e6e9ef"
+hist_sel = "#179299"
+alias = "#24273a"
+alias_sel = "#ea76cb"