Independent btn styles

[searleb]

First of all, thank you for your contribution! 😄

New feature please send pull request to feature branch, and rest to master branch.
Pull request will be merged after one of collaborators approve.
Please makes sure that these form are filled before submitting your pull request, thank you!

[中文版模板 / Chinese template]

🤔 This is a ...

• New feature
• Bug fix
• Site / document update
• Component style update
• TypeScript definition update
• Refactoring
• Code style optimization
• Branch merge
• Other (about what?)

👻 What's the background?

1. Describe the source of requirement, like related issue link.
   Edit theme variables for button border width and style independently from border-base styles.

2. Describe the problem and the scenario.
   Not able to edit the button border through variables separately from all component border styles.

💡 Solution

1. How to fix the problem, and list final API implementation and usage sample if that is an new feature.
   Added two new variables:

• @btn-border-width
• @btn-border-style
  which default to their base style counterpart

2. GIF or snapshot should be provided if includes UI/interactive modification.

📝 Changelog description

Describe changes from userside, and list all potential break changes or other risks.

1. English description
   Added @btn-border-width and @btn-border-style Less variables.

2. Chinese description (optional)

☑️ Self Check before Merge

• Doc is updated/provided or not needed
• Demo is updated/provided or not needed
• TypeScript definition is updated/provided or not needed
• Changelog is provided or not needed

[netlify]

Deploy preview for ant-design ready!

Built with commit ffc5321

https://deploy-preview-15397--ant-design.netlify.com

[codecov]

Codecov Report

Merging #15397 into feature will increase coverage by 0.04%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           feature   #15397      +/-   ##
===========================================
+ Coverage     94.1%   94.15%   +0.04%     
===========================================
  Files          250      250              
  Lines         6635     6635              
  Branches      1906     1938      +32     
===========================================
+ Hits          6244     6247       +3     
+ Misses         390      387       -3     
  Partials         1        1

Impacted Files	Coverage Δ
components/_util/wave.tsx	87.5% <0%> (+2.88%)	⬆️

---

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Δ = absolute <relative> (impact), ø = not affected, ? = missing data
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[codecov]

Codecov Report

Merging #15397 into feature will increase coverage by 0.01%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           feature   #15397      +/-   ##
===========================================
+ Coverage    94.13%   94.15%   +0.01%     
===========================================
  Files          250      250              
  Lines         6635     6635              
  Branches      1906     1938      +32     
===========================================
+ Hits          6246     6247       +1     
+ Misses         388      387       -1     
  Partials         1        1

Impacted Files	Coverage Δ
components/upload/UploadList.tsx	94.49% <0%> (-1.84%)	⬇️
components/_util/wave.tsx	87.5% <0%> (+2.88%)	⬆️

---

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 102c342...ffc5321. Read the comment docs.