Add kokkos-kernels to TChem

[mwest1066]

https://github.com/kokkos/kokkos-kernels

Needed for MTEM implementation (see #15)

[odiazib]

#27

[mwest1066]

#27

@odiazib in the description of #27 you can add the text "Resolves #22" -- this will automatically link the PR to the Issue and will also auto-close the Issue when the PR is merged. See https://docs.github.com/en/issues/tracking-your-work-with-issues/linking-a-pull-request-to-an-issue