devtool: add: fix node.js/npm handling with recipe specific sysroots

devtool: add: fix node.js/npm handling with recipe specific sysroots

The change over to recipe specific sysroots means that we can no longer
get a known location simply from configuration for the npm binary - we
need to get the recipe sysroot for nodejs-native, look there for npm if
we need to check it's present, and add that to PATH when calling out to
npm. Unfortunately this means anywhere we need to get that path we have
to have parsed all recipes, otherwise we have no reliable way of
resolving nodejs-native. Thus we have to change recipetool create to
always parse all recipes (the structure of the code does not allow us to
do this conditionally).

In the worst case, if npm hasn't already been added to its own sysroot
and we are fetching from a source repository rather than an npm
registry, this gets a bit ugly because we end up parsing recipes three
times:
1) recipetool startup, which then fetches the code and determines it's
   a node.js module, finds that npm isn't available and then exits with
   a specific error to tell devtool it needs to build npm
2) when we invoke bitbake -c addto_recipe_sysroot nodejs-native
3) when we re-invoke recipetool

This code is badly in need of refactoring, but now is unfortunately not
the time to do that, so we're going to have to live with this ugliness
for now.

Fixes [YOCTO #10992].

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>