Add .gitattributes. (#1798)

* Add .gitattributes.

This fixes spotlessCheck when checking out on windows with git core.eol=crlf and core.autocrlf=true.

Note that for git itself, the eol=lf next to the text=auto changes nothing, but spotless tries
enforce the core.eol line endings anyway.

* Adjust .gitattributes towards instrumentation's

.gitattributes

@@ -0,0 +1,7 @@
+* text=auto eol=lf
+
+*.bat text eol=crlf
+*.cmd text eol=crlf
+
+*.jar -text
+*.png -text