6/search by date

[arne-z]

This adds functionality for searching for a date, author or tags via Google Assistant, as well as Image Carousels for the responses. Still looking for refactoring advice. This requires a route expecting

params: {
    search: 
    date: 
    author: 
}

and responding with an images array of shape:

images:[
    {
      url: 'https://files.askir.me/1543849566445_Bildschirmfoto vom 2018-11-04 23-42-53.png',
      tags: ['upload', 'food', 'blub'],
      score: 0.6,
    },
]

[coveralls]

Pull Request Test Coverage Report for Build 167

• 54 of 54 (100.0%) changed or added relevant lines in 4 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-3.3%) to 96.721%

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Totals
Change from base Build 146:	-3.3%
Covered Lines:	99
Relevant Lines:	99

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💛 - Coveralls

[Adrian-St]

Please change date to start_date and end_date. Author is not supported yet, but makes sense.