Integrate the devices respository (#30974)

Despite the name of this dependency, it only handles bluetooth. Because
it's a separate repository. Integrating it, allows changes here to be
tested more consistently. In addition, it's likely that new bluetooth
libraries will allow removing the majority of the platform-specific code
in this directory.

This is based on the version of this dependency from:
https://github.com/servo/devices/pull/34

third_party/blurmac/Cargo.lock

@@ -0,0 +1,41 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
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+ "objc",
+]
+
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+
+[[package]]
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+
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+checksum = "62bb907fe88d54d8d9ce32a3cceab4218ed2f6b7d35617cafe9adf84e43919cb"
+dependencies = [
+ "libc",
+]
+
+[[package]]
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+dependencies = [
+ "malloc_buf",
+]