Add multi_ch_cal modules, optimize .gitignore.

modules/.gitignore

@@ -0,0 +1,27 @@
+# ---------------------------- Vivado & SDK common -----------------------------
+
+# ignore the vivado project
+*/*/project/*
+
+#  folders (and all of their contents) that should always be ignored,
+#  anywhere in the repo
+.Xil/
+
+#  file patterns that should always be ignored (journal files, log
+#  files, dump files that are created upon Vivado/SDK errors)
+*.jou
+*.log
+*.backup.jou
+*.backup.log
+*.upgrade_log
+*.dmp
+vivado_pid*
+*~
+
+# ------------------------------ Vivado Specific -------------------------------
+
+# preserve project tcl, compatible with both subdirectory structure
+!/*/*/project/*.tcl
+!/*/*/project/*/*.tcl
+
+# REF: https://support.xilinx.com/s/question/0D52E00006iHpHzSAK/which-files-and-folders-of-an-sdk-project-should-be-checked-into-git-and-which-ones-should-be-ignored?language=en_US