docs: update How-to section with Playground

[leohhhn]

Description

This PR updates all tutorials in the How-to section of the docs to lead and primarily use the Playground as the number one option to write Gno code.

I also fixed minor issues and updated outdated code along the way.

For all of the snippets of code shared via the Playground links, there is a unique comment at the bottom of the code, such as // How to: Deploy using Gno Playground, so that deployments can be traceable via metrics.

This PR also removes the GRC721 guide because GRC721 needs refactoring and is not very usable right now.

Latest preview of the docs: #1766 (comment)

cc @ilgooz @salmad3

Contributors' checklist...

• Added new tests, or not needed, or not feasible
• Provided an example (e.g. screenshot) to aid review or the PR is self-explanatory
• Updated the official documentation or not needed
• No breaking changes were made, or a BREAKING CHANGE: xxx message was included in the description
• Added references to related issues and PRs
• Provided any useful hints for running manual tests
• Added new benchmarks to generated graphs, if any. More info here.

[salmad3]

For creating-grc20.md: Nice:) Left some suggestions. For the text, primarily enhancements and to use imperative mode (to make it more instructional). For the realm, some nits

[leohhhn]

Latest preview of the docs: https://www.loom.com/share/e3e1bf4badcd4b7babb01cafe64ca799?sid=cc390952-e436-4b30-8ba2-1934cd8910ba

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 47.74%. Comparing base (831bb6f) to head (f872868).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1766   +/-   ##
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  Coverage   47.74%   47.74%           
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  Files         393      393           
  Lines       61629    61629           
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  Hits        29424    29424           
  Misses      29734    29734           
  Partials     2471     2471           

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[salmad3]

What do you think about breaking down full packages or realms into smaller, more digestible parts, particularly for How-To guides. This means increasing the number of code blocks that gradually build up the realm to its final state. For instance, in the case of the grc20 How-To, we could sequentially introduce the main functions in separate code blocks, which would also allow us to divide the details listed at the end into more targeted sections, making the content more engaging and easier to follow.

[zivkovicmilos]

I don't agree with this route of porting all of our user documentation to use the Playground.

There should be clear instructions on how to work with gnokey, especially specific actions like deployments and realm interactions.

I find great benefit in having documentation for the Playground present, just not as a replacement for existing tools we've built -- make sure we have them both incorporated

[leohhhn]

Status on this:

• Added playground sections to simple realm, simple package, deployment
• Updated code throughout the how to section, such as Poll package, GRC20 code
• Completely removed GRC721 tutorial until the package is refactored
• Reverted How-to test guide to its original state due to some Playground test issues right now.

cc @zivkovicmilos @salmad3