Update jupyter lite build command documentation

[mcbarton]

Description

Please include a summary of changes, motivation and context for this PR.

#336 went in without documentation changes that you now need to mount the tag files files. This PR updates the documentation about this. I also used this PR as an opportunity to add to the documentation the options the user needs to use to add the example notebooks and accompanying material (so that others can replicate the deployment xeus-cpp has).

Fixes # (issue)

Type of change

Please tick all options which are relevant.

• Bug fix
• New feature
• Added/removed dependencies
• Required documentation updates

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 81.78%. Comparing base (703be7d) to head (2ed9dc2).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #343   +/-   ##
=======================================
  Coverage   81.78%   81.78%           
=======================================
  Files          20       20           
  Lines         950      950           
  Branches       87       87           
=======================================
  Hits          777      777           
  Misses        173      173           

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