improve styling of annotationTip and annotIcon

[riedde]

• [ ] The annotationTip returns plain text at the moment (more or less) and not the annotation. The function in https://github.com/Edirom/Edirom-Online/blob/0e1a1e24584ff4ae0078884eb6cded1f95d5a2e2/add/data/xql/getAnnotation.xql#L423 is commented out and style has to be improved in general
• [x] The annotIcons are just colored at the moment, but I found the file https://github.com/Edirom/Edirom-Online/blob/develop/resources/css/annotation-style.css which asks for revision