Allow integers and strings in UIDs for Thing DSL

Signed-off-by: Alex Tugarev <telekom@tugarev.de>
Added value conversion for strings in UIDs

Signed-off-by: Alex Tugarev <telekom@tugarev.de>
Added some java doc

Signed-off-by: Alex Tugarev <telekom@tugarev.de>
Merge pull request #100 from qivicon/thing-dsl-uid

Allow integers and strings in UIDs for Thing DSL (#446481)