Cleanup - remove all the join and conditional classes and use the new utils

[daniele-zurico]

Two new utilities has been created for multiple classes and contional classes in /src/common/utils/classNames.ts

• classNames
• conditionalClassNames Where the first one is for simple usages with scenarios like:

  <div className={['a','b'].join(' ')}/>

  and the second one instead:

  <div className={['a', condition ? 'b' : 'c'].join(' ')]}

  the usage will become:

  <div className={classNames(['a','b'])}/>

  and

  <div className={['a', { 'a' : condition, 'b': !condition}]]}

  To see one example already implemented goes to /src/formSelect/FormSelect.tsx (line 196)

Scan all the components and when you find conditional classnames or concatenated classNames use the 2 explained functions

[daniele-zurico]

Closed by #411