Improve guidance on tool selection as part of the getting started experience

[droumis]

As verified by our user survey, new users coming to HoloViz are struggling to determine which tools to start with and why. Here are the tasks needed to improve this getting started experience on HoloViz.org:

Reorganize primary navigation UPDATE: Moved to #398

• Remove 'Introduction'; users can get to the homepage by clicking on the holoviz logo
• Move 'Installation' into the Tutorial and remove the outdated and tiny section that isn't about the tutorial
• Move 'Talks, 'Background', 'Tutorial', 'FAQ, into a new 'Learn' page. The current Talk page should become just one of several listed talks.
• Move 'Roadmap' as a subpage of 'Contribute'
• Rename 'Topics' as 'Topic Gallery' as 'Examples' Gallery
• Create a new 'Start Here' page for new content on choosing the appropriate HoloViz tools
• Create a new 'Blog' link
• Contingent on being able to customize the 'More' word dropdown... Replace the 'More' Dropdown with something like 'About', and nest new pages such as 'Governance', 'HEPs', 'Roadmap'. If we cannot customize 'More', nest these new pages into 'About'. Either way, ensure things work as expected on mobile.
• Order the revised main nav as follows: Start Here, Learn, Examples, Community, Contribute, Blog, About

Choosing the appropriate HoloViz tools

We hypothesize that the vast majority of new users fall into two main categories based on the most immediate phase of their data-driven work - either analyzing data or communicating results. Therefore, HoloViz.org will promote two primary entry points, hvPlot-focused workflow for data exploration and a Panel-focused workflow for dashboarding.

• Populate the new 'Start Here' page with hvPlot entry point workflow explanation for analyzing data; something like:

• Populate the new 'Start Here' page with Panel entry point workflow explanation for communicating results; something like:

[jbednar]

Looks good! For the hvPlot route, rather than "When might I need to use another HoloViz package?", I think the question is "When do I need to learn how to use other HoloViz tools directly?". I.e. often hvPlot users will use other HoloViz packages without ever knowing or caring about that, and that's ok. It's only when they want to use the API of the other package, or
want to learn specifically about that other package, do they need to go away from hvPlot.

For the Panel route, it should explain that hvPlot and HoloViews can also be used to make apps and dashboards without directly using any Panel API, and that those tools are fine for use cases like X and Y, but that using Panel's API directly is important otherwise.

[maximlt]

I like that plan :)

Just a few comments:

• 'Start Here' could be also named 'Getting Started', not sure which one is best
• The latest versions of the PyData Sphinx Theme offer more options to customize the navigation bar (see the screenshot below I just took from the 0.12.0 version). There can be external links and you can limit the number of links displayed, the remaining ones are grouped in a drop down menu (docs). Right now this theme is pinned to <= 0.9.0 (maybe <=0.10.0 in some places) across HoloViz as we override some templates and they require some updates to be compatible with the new versions. It shouldn't be too much work though, let me know if you want to have a look at that @droumis. But I think you can redesign the navigation bar assuming we're going to use the latest version of the theme.
• Assuming we use a newer version of the theme, I'd suggest putting in the dropdown menu a link to each HoloViz website.
• I'd suggest calling the gallery just 'Gallery', that's more inline with the other HoloViz sites and other similar sites (Streamlit, Bokeh). It would be a link to examples.pyviz.org. At some point examples.pyviz.org will be moved to examples.holoviz.org, but we will anyway have a redirect so you can already link it.
• Most websites I visit usually have a footer with lots of links, that seems to be a standard. In the world of Sphinx-generated website that's not true though, these sites usually have a bare and somewhat useless footer :) Mentioning that as the 'About' page is something you usually find linked in a footer. Having a nicer footer would require coming up with our own template as I believe the theme doesn't have any good option built-in.

[jbednar]

Our sites used to have footers, but they were very long and provided no additional information, so I pushed to get them removed. There is presumably still support for restoring them if they would be made useful.

I'm happy with the gallery to be just Gallery. Thanks!