adding initial base config from astrovim

lua/default_theme/plugins/gitsigns.lua

@@ -0,0 +1,7 @@
+return {
+  GitSignsAdd = { fg = C.green, bg = C.none },
+  GitSignsChange = { fg = C.orange_1, bg = C.none },
+  GitSignsDelete = { fg = C.red_1, bg = C.none },
+  MoreMsg = { fg = C.green, bold = true },
+  ModeMsg = { fg = C.grey, bold = true },
+}