UCM11 — names of standard library files should be consistent with module names

The UCM standard defines a set of standard libraries stored in 5 files (core.xml, execution.xml, interactions.xml, properties.xml and timer.xml). Inside these files, the names of the top level modules do not always match the file names (core, ext_comp_exec, interactions, std_ann, timer).
Although the standard does not states that UCM files should be named after the module they contain, it would make more sense to do so.

In addition, module names should be less generic, as UCM is designed to encourage the use of additional libraries.

Hence the standard library files may be renamed as follows:

• ucm_core.xml
• ucm_ext_exec.xml
• ucm_ext_interac.xml
• ucm_std_ann.xml
• ucm_timer.xml

update library and example declarations

Rename the modules of the standard library models:

• core becomes ucm_core
• ext_comp_exec becomes ucm_ext_exec
• interactions becomes ucm_ext_interac
• std_ann becomes ucm_std_ann
• timer becomes ucm_timer

Also add a new subsection to describe the standard port roles, introduced by UCM 1.1

Update XML and IDL code blocks to match the new module names of the standard library models