docs(wiki): initial revision (v0.1)

Contains both a first-draft of content as well as
a comprehensive GH Action to replicate from
docs/wiki to the `.wiki` sub-repo. The linting is
non-blocking at the moment.

- the existing markdown linking appears reliably
rendered in GH but more testing needed.
- style guide for contributions/expectations needs
to be added to the wiki
- **a significant re-work of the README** to
re-direct users to the Wiki is needed to avoid
doc duplication
- updates to the PR templates and contributor
guidelines to emphasize the importance of adding
documentation is still needed

.github/annotations/wiki-lint-problem-matcher.json

@@ -0,0 +1,17 @@
+{
+  "problemMatcher": [
+    {
+      "owner": "pymarkdown-error",
+      "severity": "error",
+      "pattern": [
+        {
+          "regexp": "^([^:]+):(\\d+):(\\d+):\\s+([^:]+:\\s+.+)$",
+          "file": 1,
+          "line": 2,
+          "column": 3,
+          "message": 4
+        }
+      ]
+    }
+  ]
+}