[Proposal] Make BE web site more pretty

[acelyc111]

Is your feature request related to a problem? Please describe.
Doris backends web server doesn't support to GET static file, and also doesn't support CSS style.
When we want to show more detail information on BE's web site, it's not easy to add elements. For example, as for #3714, we want to show memtrackers, it's hard to add elements and show them in a pretty style.

Describe the solution you'd like
Transfer the webserver utils which Impala and Kudu using:

• Web CSS framwork boost-table: helpful to make website more pretty
• A thirdparty library mustache: helpful to tracnslate JSON structure to html

And then do some refactor on current BE web handler.
After that, our BE web site might looks like:

[yangzhg]

could you also improve the fe webserver and change it to restful
#3314

[acelyc111]

could you also improve the fe webserver and change it to restful
#3314

I'll try if I have time, I'll reply #3314 if I start to work on it.

[morningman]

could you also improve the fe webserver and change it to restful
#3314

I'll try if I have time, I'll reply #3314 if I start to work on it.

Someone is working on FE's web server already~