fix(dubbo-ui): adapt Vue's HTML5 history mode

[yin1999]

What is the purpose of the change

Problem: we can't reload the page when the URL is not the default admin page. (Part of #482)

Resolve it by adapting Vue's HTML5 history mode, see: Vue Documentation.

Brief changelog

• adapt Vue's HTML5 history mode

Verifying this change

Run dubbo-cp and navigate to http://localhost:8888/admin/traffic/routingRule/index directly.

CheckList

• [x] Make sure there is a GitHub_issue field for the change (usually before you start working on it). Trivial changes like typos do not require a GitHub issue. Your pull request should address just this issue, without pulling in other changes - one PR resolves one issue.
• [x] Each commit in the pull request should have a meaningful subject line and body.
• [x] Write a pull request description that is detailed enough to understand what the pull request does, how, and why.
• [x] Write necessary unit-test to verify your logic correction, more mock a little better when cross module dependency exist.
• [x] GitHub Actions works fine on your own branch.
• [x] If this contribution is large, please follow the Software Donation Guide.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 8 lines in your changes missing coverage. Please review.

Project coverage is 14.89%. Comparing base (950f2aa) to head (22bd11c). Report is 49 commits behind head on master.

:exclamation: Current head 22bd11c differs from pull request most recent head 61fb21b

Please upload reports for the commit 61fb21b to get more accurate results.

Files with missing lines	Patch %	Lines
app/dubbo-ui/fs.go	0.00%	8 Missing :warning:

Additional details and impacted files

@@             Coverage Diff             @@
##           master     #489       +/-   ##
===========================================
- Coverage   33.54%   14.89%   -18.65%     
===========================================
  Files         160      589      +429     
  Lines        9474    30283    +20809     
  Branches       41       41               
===========================================
+ Hits         3178     4512     +1334     
- Misses       5955    25264    +19309     
- Partials      341      507      +166     

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