Reduce warnings shown by the Eclipse IDE

[maggu2810]

A few PRs I submitted the days has been created to fix or remove warnings shown by the Eclipse IDE.

• generic type should be parameterized #5837
• fix source folder entries #5836
• build entries must contain at least one entry #5835
• homematic: add Automatic-Module-Name #5834
• bosesoundtouch: switch statements should handle all options (ALEXA and TUNEIN missing) #5833
• remove unused private methods #5832
• fix nullness annotations to match JavaDoc #5831
• remove unused import(s) #5830
• fix potential null pointer access in classic and basic UI #5829
• ignore missing Bundle-ActivationPolicy lazy #5824
• add Automatic-Module-Name #5823

As I fixed the source folder entries (#5836) errors has been detected e.g. because tests has not been executed on the Maven build (and as I has to fix the Eclipse IDE launch configuration for that tests, it has not been executed there recently).

The annoying part of the current situation is that the number of warnings the IDE is showing results that developers ignore the warnings at all.

We should try to remove warnings that could be ignored (as e.g. done for the lazy bundle activation), move warnings to error if it should be fixed (as e.g. done for missing / wrong source folders), ...

I still would like to introduce the usage of EEAs for the ESH Eclipse IDE, so we can remove hundreds of dead code, redundant null check, ...