XXX: Extends and use monitor stack!

Also drop now needless etc/promise directory.

As possible cover promises in tests.

It comes with needed check_command_execute promise plugin.

runTestSuite.in uses _update_hash_filename_ compatbility to avoid clash with
section's filename key.

As software.cfg is extended by other software releases rename the template
part to template-neo in order to avoid clash of sections.

instance.cfg md5sum has been omitted.

_update_hash_filename_ key is used to avoid clash with recipe.

hexagonit.recipe.download is replaced with slapos.recipe.build:download in
order to have the same approach everywhere and so _update_hash_filename_ key is
used to avoid collision with section:filename.

Use _update_hash_filename_ to avoid filename clash with recipes.

_update_hash_filename_ is used to avoid conflict of section:filename key with
hexagonit.recipe.download

A lot recipes treats filename key as something special, so for them support
additional key _update_hash_filename_, in order to avoid such clash.