Improve code and fix some bugs

1. logback: add full date to messages
2. Parametrize mongodb database name
3. Change config files names to make them more explicit
4. Relational agent: add prefix to sentilo tables names and parametrize it
5. Catalog visualizer: only show info for public components and sensors
6. Catalog: improve errors messages displayed to users
7. API timestamps: force strict parsing (DateFormat lenient to false)
8. Make magic strings constants
9. Fix some other minor bugs