Move bootloader main to examples

This should remove some confusion around embassy-boot-* being a library
vs. a binary. The binary is now an example bootloader instead.

examples/boot/bootloader/stm32/Cargo.toml

@@ -0,0 +1,57 @@
+[package]
+edition = "2021"
+name = "stm32-bootloader-example"
+version = "0.1.0"
+description = "Example bootloader for STM32 chips"
+
+[dependencies]
+defmt = { version = "0.3", optional = true }
+defmt-rtt = { version = "0.3", optional = true }
+
+embassy = { path = "../../../../embassy", default-features = false }
+embassy-stm32 = { path = "../../../../embassy-stm32", default-features = false, features = ["nightly"] }
+embassy-boot-stm32 = { path = "../../../../embassy-boot/stm32", default-features = false }
+cortex-m = { version = "0.7" }
+cortex-m-rt = { version = "0.7" }
+embedded-storage = "0.3.0"
+embedded-storage-async = "0.3.0"
+cfg-if = "1.0.0"
+
+[features]
+defmt = [
+    "dep:defmt",
+    "embassy-boot-stm32/defmt",
+    "embassy-stm32/defmt",
+]
+debug = ["defmt-rtt"]
+
+[profile.dev]
+debug = 2
+debug-assertions = true
+incremental = false
+opt-level = 'z'
+overflow-checks = true
+
+[profile.release]
+codegen-units = 1
+debug = 2
+debug-assertions = false
+incremental = false
+lto = 'fat'
+opt-level = 'z'
+overflow-checks = false
+
+# do not optimize proc-macro crates = faster builds from scratch
+[profile.dev.build-override]
+codegen-units = 8
+debug = false
+debug-assertions = false
+opt-level = 0
+overflow-checks = false
+
+[profile.release.build-override]
+codegen-units = 8
+debug = false
+debug-assertions = false
+opt-level = 0
+overflow-checks = false