prs: add LOCALCOUNT to AUTOINCs migration feature

- use migrate_localcount.bbclass to generate AUTOINC entries
which are exported to LOCALCOUNT_DUMPFILE
- import the generated AUTOINC entries
- one can migrate LOCALCOUNT to AUTOINC by executing:
    bitbake-prserv-tool migrate_localcount

[YOCTO #3071]

Signed-off-by: Constantin Musca <constantinx.musca@intel.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
oe-core: add world-image feature

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
world

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>