By mistake a procedure has been named
"invert_tridiagonal" but the correct name should be
"invert_triangular"

We decided not to provide this information via the key/value store, but
rather to use the ftimings module for that.

@loh will take care to implement ftimings in the new API
@amarek wants to port the legacy API so that the old global module
  variables still contain valid values

-man pages have been updated
-man pages for legacy API are only installed if legacy API is enabled

The legacy API is has been (internally) ported to use the new interface.
The intent is that users of the legacy API do not have to change their
codes.

Next step is to completely adapt the .gitlab-ci.yml file

It was previously not possible to disable this flag

Still missing is the compatibility layer, currently it only compiles
when configure is called with

  --disable-legacy

Also, a more general solution to parameter passing via environment
variables would be nice.

This reverts commit 64ec6ec2.

There are also at least those files, where stops without 1 are present

src/elpa1/legacy_interface/elpa_cholesky_template_legacy.X90:
src/elpa1/legacy_interface/elpa_invert_trm_legacy.X90:
src/elpa1/legacy_interface/elpa_multiply_a_b_legacy.X90:
src/elpa1/legacy_interface/elpa_solve_tridi_legacy.X90:

should they be also changed?