Add templates for presentation viewer

[PrajwolAmatya]

Description

This PR adds basic templates for the presentation viewer.

Following templates are added:

1. Cover Slide Template

2. Title Content Slide Template

3. Title Content Image Slide Template

4. About Us Slide Template

Slide content fitting

The font size of the slide will be automatically reduced when the content tends to overflow out of the slide.

[individual-it]

pnpm update and then make command did not help

[PrajwolAmatya]

Can you do pnpm update revealjs-awesomd
Also can you check if setBaseUrl function is in node_modules/revealjs-awesomd/plugin/awesoMD/plugin.js just to make sure the plugin is updated.

[individual-it]

pnpm update revealjs-awesomd helped. do we need to pin the version somewhere?

[individual-it]

would be good to have a "blank" template that works just as the default reveal-js template

[individual-it]

after closing the presentation the UI of opencloud is a bit broken
before:

after opening and closing the presentation it looks like

[individual-it]

how difficult would it be to allow links here?
Currently

  - title: WWW
     text: [www.jankaritech.com](www.jankaritech.com)

makes the whole presentation to fall apart

Object { name: "YAMLException", reason: "bad indentation of a mapping entry", mark: {…}, message: "bad indentation of a mapping entry at line 7, column 10:\n         text: [www.jankaritech.com](www.jank ... \n             ^", stack: "", … }
​
mark: Object { buffer: "slide: title-content\npresenter:  JankariTech Pvt. Ltd. \nlogo: Logo-colour.png\nfooter: Markdown Presentation Viewer\naboutUs:\n  - title: WWW\n     text: [www.jankaritech.com](www.jankaritech.com)\n  - title: linkedin\n    text: www.linkedin.com/company/jankaritech\n  - title: facebook\n    text: www.facebook.com/jankaritech\n\u0000", position: 148, line: 6, … }
​
message: "bad indentation of a mapping entry at line 7, column 10:\n         text: [www.jankaritech.com](www.jank ... \n             ^"
​
name: "YAMLException"
​
reason: "bad indentation of a mapping entry"

If links are not supported that is fine, but the presentation should not break

[individual-it]

Doing something invalid here, e.g text:www.jankaritech.com leads now to this error:

YAMLException: can not read an implicit mapping pair; a colon is missed at line 7, column 29: text:www.jankaritech.com ^

it gives some hint, but might still be hard for users to understand. Do we want to accept that kind of error message for now?

[individual-it]

Let's add tests for the templating to make sure all these corner cases don't break

[PrajwolAmatya]

I have addressed the issues and fixed them. Most of the fixes needed to done in the plugin (PR: opf/revealjs-awesoMD#24).

Let's add tests for the templating to make sure all these corner cases don't break

Will work on it. 👍

@individual-it

[individual-it]

anything shown to the user e.g. error messages should be sanitized.

currently I can do:

# This template does not exist and has special char  ::slide:<a href="jankari.tech">jankaritech</a>

and the browser will render <a href="jankari.tech">jankaritech</a> as HTML

[individual-it]

sometimes the logo works sometimes not

I am using

---
slide: title-content
presenter:  JankariTech Pvt. Ltd. 
logo: images/Logo-colour.png

and the file images/Logo-colour.png does exist.

the URL of the logo in the presentation is sometimes: https://localhost:9200/images/Logo-colour.png but after a reload correctly blob:https://localhost:9200/9db3f52b-2d67-4be4-b116-9a94f6798c7

[PrajwolAmatya]

anything shown to the user e.g. error messages should be sanitized.

currently I can do:

# This template does not exist and has special char  ::slide:<a href="jankari.tech">jankaritech</a>

and the browser will render <a href="jankari.tech">jankaritech</a> as HTML

Fixed it in PR opf/revealjs-awesoMD#25.

The fix for this is in PR opf/revealjs-awesoMD#25.