Contents of INST not getting installed during R package install

Question

I am having trouble getting the contents of my INST folder to copy over to the root folder of the package (or copy over in general)

My R package depends on two java packages and their jars, these are both included as follows:

PackageTest
+-- inst
|   +-- impala-jdbc-cdh5
    |    +-- *.jar
|   +-- sqlserver-jdbc-4
    |    +-- *.jar
+-- R
|   +-- hello.R
+-- man
|   +-- hello.Rd
+-- DESCRIPTION  
+-- NAMESPACE
+-- .Rbuildignore

From my understanding the contents of the Package/inst folder should be moved to the root of the folder on install resulting in a folder structure that looks like this:

PackageTest
+-- impala-jdbc-cdh5
|    +-- *.jar
+-- sqlserver-jdbc-4
    +-- *.jar
+-- R
|   +-- PackageTest
|   +-- PackageTest.rdb
|   +-- PackageTest.rdx
+-- Meta
+-- html
+-- help
+-- DESCRIPTION  
+-- NAMESPACE
+-- INDEX

Instead I am missing the two folders listed at the top:

PackageTest
+-- R
|   +-- PackageTest
|   +-- PackageTest.rdb
|   +-- PackageTest.rdx
+-- Meta
+-- html
+-- help
+-- DESCRIPTION  
+-- NAMESPACE
+-- INDEX

There are other files in the other folders, but nothing that I am concerned with.

What I have tried:

I am using RStudio to generate this package and all I am doing is modifying the DESCRIPTION package to include the two Java packages. (so it really is a stub package with some Java jars - I have also imported rJava)

To build and install the package I have tried using devtools::build and devtools:install and the shortcuts that RStudio provides (Ctrl + Shift + B).

I have also tried to upload this repo onto our internal Git repo and use devtools::install_git and that results in the same issue.

Restructuring the inst folder to so that all the jars are in inst/Java has not helped with my issue.

Lastly, the package we have deployed on our production repo is bundled the exact same as the first example and we have no issues using the impala and sql drivers.

Any help would be appreciated. :)

EDIT:

.Rbuildignore

^.*\.Rproj$
^\.Rproj\.user$