devtool: add: build nodejs-native if npm is needed and not available

devtool: add: build nodejs-native if npm is needed and not available

If the user runs devtool add on an npm:// URL (or source tree that uses
node.js), and npm is not available, just build nodejs-native instead of
telling the user they need to do it; if that fails because there isn't
any such recipe (which would be the default, since it's not in OE-Core)
then produce a slightly more readable error message hinting at what the
user needs to do.

Note that this forces the use of nodejs-native rather than npm on the
host - this makes sense for two reasons: (1) we need it to be compatible
with nodejs for the target, and (2) we have to have a recipe for that
anyway, so allowing you to avoid having a recipe for the native version
isn't really beneficial.

There's a bit of a hack in here in order to allow this - for node.js
sources that aren't fetched via npm we don't know that they are that
until we've fetched and unpacked them, by which time we're inside
recipetool and have an active tinfoil instance that will prevent bitbake
being run. To avoid this being an issue, we allow recipetool to get to
the point where we know we need npm and then exit with a specific exit
code, at which point devtool can try to build it and then if that
succeeds, it will re-execute recipetool. This is definitely not ideal,
but it can't really be refactored and done properly until we do the
tinfoil2 refactoring; in the mean time though we still want to be
helpful to the user.

Fixes [YOCTO #10337].

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