[Web Portal] Remove admin-lte layout dependencies

[sunqinzheng]

Most pages in web portal are using react and office-fabric framework now.
And our layout component (sidebar, navbar, background) still uses admin-lte which style pattern is different from office fabric/fluent.
I think it is time to remove the admin-lte depenedencies now.

TODO

• Refactoring the layout component using office fabric and remove admin lte dependencies
• Use ejs loader to implement a wrapper workaround for old jquery/ejs based pages.
• Remove unused pages in web portal
• Reorganize the polyfills and initialize functions (theme/font)

[sunqinzheng]

#4057