ui/ux: homogenizes parts of the ui

- makes chat messages selectable
- changes ui colors to the Ring blue shades
- attempts to resize the window appropriately at app start
- adds confirmation modals for removing converstations and contacts
- corrects and error in the debug logger
- corrects vcardutils not handling JPEGs

Change-Id: I2c8a63f9c18c734a25dfd61086b137143cdac659
Tuleap: #790