Make module for filtering posts on a search page

[erikbasargin]

Describe the solution you'd like

• [x] Implement page & store (FilterView #35 /FilterStore) in the HomeFlow module
• [x] FilterStore should live in PageStore and connect with the PageFetcher #49
• [x] Update FilterView to new icons of checkmarks #53
• [ ] Prepare PageFetcher & StackexchangeNetworkService to work with filters
• [ ] Add FilterMenu with custom fast filters - It should be connected with the same FilterStore through special intention functions
• [ ] FilterStore should update global title on a search page

Additional context

• Example of functionality