chore: drop few redundant gitignore entries

.gitignore

@@ -12,16 +12,12 @@ ebin
 !ebin/.placeholder
 .concrete/DEV_MODE
 .rebar
-test/ebin/*.beam
 .exrc
-plugins/*/ebin
 *.swp
 *.so
 .erlang.mk/
 cover/
-eunit.coverdata
 test/ct.cover.spec
-ct.coverdata
 .idea/
 _build
 .rebar3