[GR-378] Create an internal package repo for package tests

.gitignore

ci.hocon

...src/com/oracle/truffle/r/engine/shell/RscriptCommand.java

...uffle.r.runtime/src/com/oracle/truffle/r/runtime/DCF.java

....r.runtime/src/com/oracle/truffle/r/runtime/REnvVars.java

...untime/src/com/oracle/truffle/r/runtime/RStartParams.java

com.oracle.truffle.r.test.native/Makefile

com.oracle.truffle.r.test.native/packages/Makefile

com.oracle.truffle.r.test.native/packages/PACKAGES

com.oracle.truffle.r.test.native/packages/Rutils/template.R

com.oracle.truffle.r.test.native/packages/package.mk

com.oracle.truffle.r.test.native/packages/pkg-filelist

...ffle.r.test.native/packages/testrffi/testrffi/DESCRIPTION

...native/packages/testrffi/testrffi/man/testrffi-package.Rd

....r.test.native/packages/testrffi/testrffi/man/testrffi.Rd

...uffle.r.test.native/packages/testrffi/testrffi/src/init.c

....test.native/packages/testrffi/testrffi/tests/asTests.Rin

...t.native/packages/testrffi/testrffi/tests/coerceTests.Rin

...est.native/packages/testrffi/testrffi/tests/simpleTests.R

...fle.r.test.native/packages/vanilla/vanilla/man/vanilla.Rd