Add filter for compagnies and contacts, create filter trait

[homersimpsons]

Hi, Thank you for this lib !

I found there are some missing endpoints to filter:

• https://developers.freshdesk.com/api/#filter_contacts
• https://developers.freshdesk.com/api/#filter_companies
• https://developers.freshdesk.com/api/#filter_tickets (was under search)

Let me know if anything is wrong :)

(I didn't generate the doc)

[OneHatRepo]

Please merge this into master.

[Jewhurst]

Please merge

[guyoron]

Please merge this!