Add target parameter to link() function

[acicovic]

This PR adds the ability to specify a target attribute within the link() function, which allows the opening of the page in a new tab.

Note: This shouldn't break any existing code as the argument is optional.

For example:

// Open in new tab
$app->add(['Label', 'Open page in a new tab'])->link(['my-page'], '_blank');

// Open in same tab as before
$app->add(['Label', 'Open page in a new tab'])->link(['my-page']);

[codecov]

Codecov Report

Merging #791 into develop will decrease coverage by 0.01%.
The diff coverage is 50%.

@@              Coverage Diff              @@
##             develop     #791      +/-   ##
=============================================
- Coverage      71.26%   71.25%   -0.02%     
- Complexity      2242     2243       +1     
=============================================
  Files            119      119              
  Lines           5325     5326       +1     
=============================================
  Hits            3795     3795              
- Misses          1530     1531       +1

Impacted Files	Coverage Δ	Complexity Δ
src/jsSearch.php	85% <0%> (ø)	5 <1> (ø)	⬇️
src/View.php	85.25% <75%> (-0.26%)	143 <3> (+1)

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[romaninsh]

makes sense..