Consolidate in-repo documentation (#3143)

* move doc/misc to top level, add READMEs

* Move docs -> doc/devel

This also consolidates the _three_ documents describing (differently)
how to build Taskwarrior into a signle document.

doc/devel/contrib/first_time.md

@@ -0,0 +1,68 @@
+# Welcome, Open Source Contributor
+
+Welcome, potential new Open Source contributor! This is a guide to show you exactly how to make a contribution, and will lead you through the entire process.
+
+There are many people who wish to start contributing, but don't know how or where to start.
+If this might be the case for you, then please read on, this guide is for you.
+Because we want you to join in the fun with Open Source - it can be fun and rewarding, improve your skills, or just give you a way to contribute back to a project.
+
+## How to Help
+
+Help is needed in all areas of Taskwarrior development - design, coding, testing, support and marketing.
+Applicants must be friendly.
+Perhaps you are looking to help, but don't know where to start.
+Perhaps you have skills we are looking for, here are ways you may be able to help:
+
+-   Use Taskwarrior, become familiar with it, and make suggestions.
+    We get great feedback from both new users and veteran users.
+    New users have a fresh approach that we can no longer achieve, while veteran users develop clever and crafty ways to use the product.
+
+-   Report bugs and odd behavior when you see it.
+    We don't necessarily know it's broken, unless you tell us.
+
+-   Suggest enhancements.
+    We get lots of these, and it's great.
+    Some really good ideas have been suggested and implemented.
+    Sure, some are out of scope, or plain crazy, but the stream of suggestions is fascinating to think about.
+
+-   Participate in the [bug tracking](https://github.com/GothenburgBitFactory/taskwarrior/issues) database, to help others and maybe learn something yourself.
+
+-   Proofread the documentation and man pages.
+
+-   Improve the documentation.
+
+-   Improve the man pages.
+
+-   Help improve the tutorials.
+    Make your own tutorial.
+
+-   Confirm a bug.
+    Nothing gets fixed without confirmation.
+
+-   Refine a bug.
+    Provide relevant details, elaborate on the behavior.
+
+-   Fix a bug.
+    Send a patch.
+    For this you'll need to know some C++ or Rust, and understand the [GitHub flow](https://docs.github.com/en/get-started/quickstart/github-flow).
+    See [Developing Taskwarrior](./development.md) for more information.
+    We welcome all bug fixes, provided the work is done well and doesn't create other problems or introduce new dependencies.
+    We recommend talking to us before starting: we are happy to help you out!
+
+-   Write a unit test.
+    Unit tests are possibly the most useful contributions of all, because they not only improve the quality of the code, but prevent future regressions, therefore maintaining quality of subsequent releases.
+    Plus, broken tests are a great motivator for us to fix the causal defect.
+    You'll need Python skills.
+
+-   Spread the word.
+    Help others become more effective at managing tasks.
+    Share your methodology, to inspire others.
+
+-   Encouragement.
+    Tell us what works for you, and what doesn't.
+    It's all good.
+
+-   Donate! Help offset costs.
+
+Please remember that we need contributions from all skillsets, however small.
+Every contribution helps.