[improve] update grafana auth method and add expose url

[tomsun28]

What's changed?

• update api auth method

for some maybe use xxx@xxx as password, it will work failed when pre auth method.

• add expose url param

for some env the inner access grafana server url and extern access url may not same.

Checklist

• I have read the Contributing Guide
• I have written the necessary doc or comment.
• I have added the necessary unit tests and all cases have passed.

Add or update API

• I have added the necessary e2e tests and all cases have passed.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 6 lines in your changes missing coverage. Please review.

Project coverage is 32.55%. Comparing base (9a00f5a) to head (8e05694).

Files with missing lines	Patch %	Lines
.../history/vm/VictoriaMetricsClusterDataStorage.java	0.00%	3 Missing ⚠️
...e/store/history/vm/VictoriaMetricsDataStorage.java	0.00%	3 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #2818      +/-   ##
============================================
- Coverage     32.56%   32.55%   -0.02%     
  Complexity     1903     1903              
============================================
  Files           496      496              
  Lines         18310    18314       +4     
  Branches       2249     2251       +2     
============================================
- Hits           5963     5962       -1     
- Misses        11651    11654       +3     
- Partials        696      698       +2     

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