doc: massive refactor and simplification to migrate to mkdocs

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

doc/index.md

@@ -0,0 +1,73 @@
+Introduction
+============
+
+> Reverse engineered from the [EeePC fastinit][]  
+> "gaps filled with frog DNA …"  
+> — [Claudio Matsuoka][]
+
+Finit is a process starter and [supervisor][1] designed to run as PID 1
+on Linux systems.  It consists of a set of [plugins](plugins.md) and can
+be set up using [configuration files](config/files.md).  Plugins start
+at [hook points](plugins.md#hooks) and can run various set up tasks
+and/or install event handlers that later provide runtime services, e.g.,
+PID file monitoring, or [conditions](conditions.md).
+
+Features include:
+
+  * [Runlevels][5], defined per service
+  * One-shot tasks, services (daemons), or [SysV init][4] start/stop scripts
+  * Runparts and `/etc/rc.local` support
+  * Process supervision similar to [systemd][]
+  * Sourcing environment files
+  * Conditions for network/process/custom dependencies
+  * Readiness notification; PID files (native) for synchronizing system
+    startup, support for systemd [sd_notify()][], or [s6 style][] too
+  * Limited support for [tmpfiles.d(5)][] (no aging, attributes, or subvolumes)
+  * Pre/Post script actions
+  * Rudimentary [templating support](config/templating.md)
+  * Tooling to enable/disable services
+  * Built-in getty
+  * Built-in watchdog, with support for hand-over to [watchdogd][]
+  * Built-in support for Debian/BusyBox [`/etc/network/interfaces`][3]
+  * Cgroups v2, both configuration and monitoring in `initctl top`
+  * Plugin support for customization
+  * Proper rescue mode with bundled `sulogin` for protected maintenance shell
+  * Integration with [watchdogd][] for full system supervision
+  * Logging to kernel ring buffer before `syslogd` has started, see the
+    recommended [sysklogd][] project for complete logging integration
+	and how to log to the kernel ring buffer from scripts using `logger`
+
+For a more thorough overview, see the [Features](features.md) section.
+
+> [!TIP]
+> See [SysV Init Compatibility](config/sysv.md) for help to
+> quickly get going with an existing SysV or BusyBox init setup.
+
+
+Origin
+------
+
+This project is based on the [original finit][] by [Claudio Matsuoka][]
+which was reverse engineered from syscalls of the [EeePC fastinit][].
+
+Finit is developed and maintained by [Joachim Wiberg][] at [GitHub][6].
+Please file bug reports, clone it, or send pull requests for bug fixes
+and proposed extensions.
+
+
+
+[1]:                https://en.wikipedia.org/wiki/Process_supervision
+[3]:                https://manpages.debian.org/unstable/ifupdown2/interfaces.5.en.html
+[4]:                https://en.wikipedia.org/wiki/Init
+[5]:                https://en.wikipedia.org/wiki/Runlevel
+[6]:                https://github.com/troglobit/finit
+[systemd]:          https://www.freedesktop.org/wiki/Software/systemd/
+[sd_notify()]:      https://www.freedesktop.org/software/systemd/man/sd_notify.html
+[s6 style]:         https://skarnet.org/software/s6/notifywhenup.html
+[tmpfiles.d(5)]:    https://www.freedesktop.org/software/systemd/man/tmpfiles.d.html
+[EeePC fastinit]:   https://web.archive.org/web/20071208212450/http://wiki.eeeuser.com/boot_process:the_boot_process
+[original finit]:   http://helllabs.org/finit/
+[Claudio Matsuoka]: https://github.com/cmatsuoka
+[Joachim Wiberg]:   https://troglobit.com
+[watchdogd]:        https://troglobit.com/watchdogd.html
+[sysklogd]:         https://github.com/troglobit/sysklogd/