nit: add license, gitignore, & source.el to modules

This is to prep our modules to be moved to their own repo in the
future (doomemacs/modules).

modules/.gitignore

@@ -0,0 +1,19 @@
+.DS_Store
+.idea
+*.log
+tmp/
+*~
+*.*~
+\#*
+.\#*
+*.cache*
+*.log
+test/.local*/
+test/result
+
+# compiled files
+*.elc
+*.lib
+*.fas
+*.dat
+*.eld

modules/LICENSE

@@ -0,0 +1,22 @@
+The MIT License (MIT)
+
+Copyright (c) 2021 Henrik Lissner
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

modules/source.el

@@ -0,0 +1,7 @@
+;; This file supplies some metadata about this module repo to Doom's module
+;; manager. None of them are required, but it's a good idea to include them so
+;; Doom can perform some sanity checks for you.
+
+:root     "./"     ; where the module tree starts
+:version  "21.12"  ; version of this repo
+:requires "3.0.0"  ; minimum supported version of Doom's core