workspace layout improved

* meta-hipos replaced by submodule
* hipos-base added for adapted managment files

Signed-off-by: Ralf Schröder <schroeder@dresearch-fe.de>
Signed-off-by: Steffen Sledz <sledz@dresearch-fe.de>
HYP-6855 Build environment initialization improved

The hipos layer specific parts are moved to hipos-base.
The build directory is now temporary, all configs are generated.
The new structure allows a simple introduction of own (non public) layers.

Signed-off-by: Ralf Schröder <schroeder@dresearch-fe.de>
cleanup naming for helper scripts and build directories

Use 'init' prefix for scripts initializing or updating the workspace
and 'setup' for generated scripts setting up the build environment
to avoid confusion.

Use 'open' postfix for builds of this FOSS personality. If you
adapt this for closed source builds use 'closed' here.

Signed-off-by: Steffen Sledz <sledz@dresearch-fe.de>
Acked-by: Angelika Tobisch <tobisch@dresearch-fe.de>