Initial setup for PID control.

Copied file from https://github.com/braincore/pid-rs as it's very small and simple, and we'll want to make some modifications.

Cargo.toml

@@ -24,7 +24,10 @@ readme = "README.md"
 license = "MIT"
 
 #----- no-std ----------------------------------
-# Math
+# Numbers
+[workspace.dependencies.num-traits]
+version = "0.2.*"
+default-features = false
 [workspace.dependencies.libm]
 version = "0.2.*"
 # Units of measurement
@@ -47,6 +50,11 @@ version = "1.0.*"
 # Memory
 [workspace.dependencies.static_cell]
 version = "2.1.*"
+# Serioalization
+[workspace.dependencies.serde]
+version = "1.0.*"
+default-features = false
+features = ["derive"]
 # Other embedded utilities
 [workspace.dependencies.cortex-m]
 version = "0.7.*"
@@ -106,10 +114,13 @@ license.workspace = true
 [features]
 thermocouple_k = []
 lm35 = []
+pid = []
 
 [dependencies]
 uom = { workspace = true }
+num-traits = { workspace = true }
 libm = { workspace = true }
+serde = { workspace = true, optional = true }
 
 #---------------------------------------------------------------------------------------------------------------------
 #----- Profiles ------------------------