Monotonic rewrite (#874)

* Rework timer_queue and monotonic architecture

Goals:
 * make Monotonic purely internal
 * make Monotonic purely tick passed, no fugit involved
 * create a wrapper struct in the user's code via a macro that then
   converts the "now" from the tick based monotonic to a fugit based
   timestamp

We need to proxy the delay functions of the timer queue anyway,
so we could simply perform the conversion in those proxy functions.

* Update cargo.lock

* Update readme of rtic-time

* CI: ESP32: Redact esp_image: Too volatile

* Fixup: Changelog double entry rebase mistake

---------

Co-authored-by: Henrik Tjäder <henrik@tjaders.com>

rtic-time/README.md

@@ -0,0 +1,29 @@
+# rtic-time
+
+Basic definitions and utilities that can be used to keep track of time.
+
+[![crates.io](https://img.shields.io/crates/v/rtic-time)](https://crates.io/crates/rtic-time)
+[![docs.rs](https://docs.rs/rtic-time/badge.svg)](https://docs.rs/rtic-time)
+[![matrix](https://img.shields.io/matrix/rtic:matrix.org)](https://matrix.to/#/#rtic:matrix.org)
+
+
+## Content
+
+The main contribution of this crate is to define the [`Monotonic`](https://docs.rs/rtic-time/latest/rtic_time/trait.Monotonic.html) trait. It serves as a standardized interface for libraries to interact with the system's monotonic timers.
+
+Additionally, this crate provides tools and utilities that help with implementing monotonic timers.
+
+## Implementations of the `Monotonic` trait
+
+For implementations of [`Monotonic`](https://docs.rs/rtic-time/latest/rtic_time/trait.Monotonic.html)
+on various hardware, see [`rtic-monotonics`](https://docs.rs/rtic-monotonics/).
+
+
+## Chat
+
+Join us and talk about RTIC in the [Matrix room][matrix-room].
+
+Weekly meeting minutes can be found over at [RTIC HackMD][hackmd].
+
+[matrix-room]: https://matrix.to/#/#rtic:matrix.org
+[hackmd]: https://rtic.rs/meeting