beginning of RTP refactoring and cleaning. Removed EXP via diagonalization, added convinience function to perform a complex gemm using fm matrices (Samuel Andermatt)

git-svn-id: svn://svn.code.sf.net/p/cp2k/code/trunk@13519 bac0169d-1eea-4375-b5f6-f89d2ced9994