feat(VTreeview): **color** prop

[jacekkarczmarczyk]

Motivation and Context

fixes #7613

How Has This Been Tested?

playground

Markup:

<template>
  <div class="ma-5 pa-5">
    <v-treeview v-model="selected" rounded :active="selected" :items="treeItems" color="primary" activatable selectable hoverable />
    <v-divider />
    <v-treeview :items="treeItems" shaped color="red" activatable hoverable open-on-click />
  </div>
</template>

<script>
  export default {
    data: () => ({
      selected: [],
      treeItems: [
          {
            id: 1,
            name: 'Applications:',
            children: [
              { id: 2, name: 'Calendar' },
              {
                id: 3,
                name: 'Chrome',
                children: [
                  { id: 4, name: 'Foo', disabled: true },
                  { id: 5, name: 'Bar' },
                  { id: 6, name: 'Baz' }
                ],
              },
              { id: 7, name: 'Webstorm' }
            ]
          },
          {
            id: 8,
            name: 'Also applications:',
            disabled: true,
            children: [
              { id: 9, name: 'Calendar' },
              { id: 357, name: 'Chrome' },
            ]
          },
        ]
    }),
  }
</script>

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Improvement/refactoring (non-breaking change that doesn't add any feature but make things better)

Checklist:

• The PR title is no longer than 64 characters.
• The PR is submitted to the correct branch (master for bug fixes and documentation updates, dev for new features and breaking changes).
• My code follows the code style of this project.
• I've added relevant changes to the documentation (applies to new features and breaking changes in core library)

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TravisBuddy Request Identifier: 12a717e0-9663-11e9-9418-53fb1d2732c3

[codecov]

Codecov Report

Merging #7617 into next will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##             next    #7617      +/-   ##
==========================================
+ Coverage   86.93%   86.93%   +<.01%     
==========================================
  Files         326      326              
  Lines        8536     8537       +1     
  Branches     2153     2154       +1     
==========================================
+ Hits         7421     7422       +1     
  Misses       1025     1025              
  Partials       90       90

Impacted Files	Coverage Δ
.../vuetify/src/components/VTreeview/VTreeviewNode.ts	98.68% <100%> (+0.01%)	⬆️

---

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[codecov]

Codecov Report

Merging #7617 into next will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##             next    #7617      +/-   ##
==========================================
+ Coverage   86.93%   86.94%   +<.01%     
==========================================
  Files         326      326              
  Lines        8536     8538       +2     
  Branches     2153     2154       +1     
==========================================
+ Hits         7421     7423       +2     
  Misses       1025     1025              
  Partials       90       90

Impacted Files	Coverage Δ
.../vuetify/src/components/VTreeview/VTreeviewNode.ts	98.7% <100%> (+0.03%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update ffdb48c...6ff83fc. Read the comment docs.

[jacekkarczmarczyk]

Should we have a separate prop for text/background (color) and checkbox (selectedColor) or should they be merged into 1 color prop? @vuetifyjs/core-team.

[MajesticPotatoe]

I think 2 props may be better.

[dsseng]

merge 9&10 into one line and use :: as a good CSS3 practice