Support for interactive presentation master/slave

[TomasKulhanek]

• educator mode (separate.html) - may set 'hash' i.e. document to be viewed by students
• student mode (index.html) - may view only one page, based on what educator set

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• firebase configuration component - bdl-fb-config
• encrypt firebase configuration component -<bdl-fb-config api-str="...."></bdl-fb-config>
• component to set state, present as button, educator mode will do it - <bdl-set-state title="State 1" value="state1.md">...
• component to get state, present as hidden, student mode - <bdl-get-state tohash="true">...
• firebase config to listen new state, via websockets - attribute listen="true"
• option to hide nav icon - attribute showicon in markdown-

[TomasKulhanek]

Sample app for DKA is at https://egolem.online/dka/
For educator mode append educator.html to the previous address

[TomasKulhanek]

• bind question with tabs [ questionid and tabid separated by ';'
• setAnswer,addAnswer,removeAnswer with questionid and tabid is not processed properly, fix it
• send answer to firebase realtime db

[TomasKulhanek]

• some ipads do not follow screen change, after connecting them to MacOS and enable developer console, Safari shows 'crypto.randomUUID() is not a function'.
• add custom generate uuid implementation