Add the wiki, Quality and Release workflows

Add a wiki/ folder with a .publish marker for the shared Publish wiki
workflow, a Quality workflow (shellcheck and shfmt through the shared
reusable workflow) and a manual Release workflow that builds the release
page from CHANGELOG.md.

Set switch_case_indent for *.sh in .editorconfig so shfmt accepts the
existing case layout.

CHANGELOG.md

@@ -0,0 +1,23 @@
+# Changelog
+
+All notable changes to RepoFoundry. Versions are tags `vMAJOR.MINOR.PATCH`.
+The release workflow takes the text of a release page from the entry of its
+version, so every release needs an entry here before it is started.
+
+Each release lists its changes in these groups, in this order: **Breaking**,
+**Added**, **Changed**, **Fixed**. A release with a Breaking entry has a new
+major version.
+
+`python tools/changelog.py check` of `TirSystem/github-action` verifies this
+file.
+
+## [Unreleased]
+
+### Added
+
+- Gitea workflows: Quality (shellcheck and shfmt through the shared reusable
+  workflow) and Release (tag and release page from this changelog).
+- A `wiki/` folder with a `.publish` marker, published to the Gitea wiki by the
+  shared Publish wiki workflow.
+- `switch_case_indent` for `*.sh` in `.editorconfig`, so `shfmt` accepts the
+  existing layout of `case` branches.