lobster shall support codebeamer items without summary

[phiwuu]

Currently lobster-codebeamer creates an error message if the codebeamer item does not have a summary, see

lobster/lobster/tools/codebeamer/codebeamer.py

Line 200 in 64104c5

req.error("Item lacks a summary text")

However, it is a legit use case to have codebeamer items without a summary. For example, some projects might decide to use only the description in codebeamer, and keep the summary empty. A possible reason for such a decision could be that, the requirements have been migrated from another database into codebeamer, and there was no summary field available in the previous database.

lobster-codebeamer currently creates a message in the resulting JSON file, and lobster-report then ignores the item in the computation of the coverage, and lobster-html-report prints an error message into the HTML report.

Hence I recommend to remove the restriction from lobster-codebeamer.