CI build analysis: print log file errors

The generated HTML from CI builds so far only shows the number of
errors, but not the errors themselves. This is inconvenient, as this
means that developers have to go to the logs.

This commit modifies AnalyzeBuildLogs(), which already iterates the
entire file, to store the lines containing "error:" (as it would be
emitted by a compiler). The callers of AnalyzeBuildLogs() now also print
the analysis outcome in a more concise manner.

Also, change the return parameter of AnalyzeBuildLogs() to a tuple to make
the variable handling easier, and remove the unused warnings list.

ci-scripts/cls_cluster.py

@@ -397,9 +397,9 @@ class Cluster:
 		# Analyze the logs
 		collectInfo = {}
 		for image, lf in log_files:
-			ret = cls_containerize.AnalyzeBuildLogs(image, lf)
-			imgStatus = ret['status']
-			msg = f"size {imageSize[image]}, analysis of {os.path.basename(lf)}: {ret['errors']} errors, {ret['warnings']} warnings"
+			imgStatus, errors = cls_containerize.AnalyzeBuildLogs(image, lf)
+			info = f"Analysis of {os.path.basename(lf)}: {imgStatus=}, size {imageSize[image]}, {len(errors)} errors"
+			msg = "\n".join([info] + errors)
 			HTML.CreateHtmlTestRowQueue(image, 'OK' if imgStatus else 'KO', [msg])
 			status = status and imgStatus