fix some typos and add basic nginx authentication doc

[Hearen]

#15

After typing correct account, you can then enter:

Chrome might cached the account, so you can test it with incognito window

[codecov-io]

Codecov Report

Merging #226 into master will decrease coverage by 0.25%. The diff coverage is n/a.

@@            Coverage Diff            @@
##           master    #226      +/-   ##
=========================================
- Coverage    4.86%   4.61%   -0.26%     
=========================================
  Files         221     190      -31     
  Lines       10950    9347    -1603     
  Branches     1939    1620     -319     
=========================================
- Hits          533     431     -102     
+ Misses      10366    8873    -1493     
+ Partials       51      43       -8

Impacted Files	Coverage Δ
...thas/core/command/klass100/ClassLoaderCommand.java	0% <0%> (ø)	:arrow_up:
...o/arthas/core/command/monitor200/TraceCommand.java	0% <0%> (ø)	:arrow_up:
...n/java/com/taobao/arthas/core/util/ThreadUtil.java	0% <0%> (ø)	:arrow_up:
...ao/arthas/core/command/express/ExpressFactory.java	0% <0%> (ø)	:arrow_up:
.../taobao/arthas/core/shell/cli/CompletionUtils.java	0% <0%> (ø)	:arrow_up:
.../java/com/taobao/arthas/core/util/SearchUtils.java	0% <0%> (ø)	:arrow_up:
...aobao/arthas/core/command/klass100/JadCommand.java	0% <0%> (ø)	:arrow_up:
...rthas/core/command/monitor200/TimeTunnelTable.java	0% <0%> (ø)	:arrow_up:
.../java/com/taobao/arthas/core/advisor/Enhancer.java	0% <0%> (ø)	:arrow_up:
...arthas/core/command/klass100/DumpClassCommand.java	0% <0%> (ø)	:arrow_up:
... and 70 more

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[ralf0131]

Hi, sorry for the late reply.

I just finished my busy work for the Double eleven shopping festival. I am planning to back to the Arthas community. I'd like to continue on reviewing the existing pull request within days, please ping me if there is no progress.

[CLAassistant]

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