Improve style

Front-end style:

• Create network button in primary color and active.
• Create network button text change to Select network form FDSN.
• More space between title and content of page -> use <hr>
• Remove css main-heigh and size-ok. Replace by div + strecht
• Change DOI color in Network list to secondary/light
• Welcome page : 'DALIMA'
• Remove : after each title
• Funding reference : 2nd title corresponds to identifier
• Remove citation from detail or externalise it.
• Tomselects : select intermediary selections (otherwise we have to delete all from last).

Code style:

• Replace X.str() to str(X)
• Replace number_of_xxx to xxx_number