Invalid features on server with no warning

[turkeylurkey]

In this case we have an invalid project with EE8 specified in the build file (pom.xml or build.gradle) and with a generated-features.xml file in src/main/liberty/config/configDropins/overrides dir where the features specified are for EE7. E.g. demo-devmode.

When we start dev mode with clean task/mojo and no options, generate-features is on by default and generateToSrc is off by default. Dev mode compiles the source files for EE8 and generates the features for EE8 in the server dir as normal. Then deploy runs and copies all the config files from the src dir including the invalid generated-features.xml file.

When generate features runs it ignores the existing generated-features.xml file by design so it is not considered by the binary scanner's error detection algorithm.

Possibly related to #1976.

[turkeylurkey]

Should print an error message on startup. We would need to detect that there is this file that will overwrite the generated features file. The error message should say something like "Detected a configuration file in the src dir that will overwrite the generated features file. You must use the generateToSrc option to use the src dir or remove the generated-features.xml file in the src dir if you need to generate to the server dir."

[turkeylurkey]

Consider checking for this file every time we change a file (Java or config) and generate features.