util: Add ParseUInt32 and ParseUInt64

Add error and range-checking parsers for unsigned 32 and 64 bit numbers.
The 32-bit variant is required for parsing sequence numbers from the
command line in `bitcoin-tx` (see #8164 for discussion). I've thrown in
the 64-bit variant as a bonus, as I'm sure it will be needed at some
point.

Also adds tests, and updates `developer-notes.md`.

src/utilstrencodings.h

@@ -70,6 +70,20 @@ bool ParseInt32(const std::string& str, int32_t *out);
  */
 bool ParseInt64(const std::string& str, int64_t *out);
 
+/**
+ * Convert decimal string to unsigned 32-bit integer with strict parse error feedback.
+ * @returns true if the entire string could be parsed as valid integer,
+ *   false if not the entire string could be parsed or when overflow or underflow occurred.
+ */
+bool ParseUInt32(const std::string& str, uint32_t *out);
+
+/**
+ * Convert decimal string to unsigned 64-bit integer with strict parse error feedback.
+ * @returns true if the entire string could be parsed as valid integer,
+ *   false if not the entire string could be parsed or when overflow or underflow occurred.
+ */
+bool ParseUInt64(const std::string& str, uint64_t *out);
+
 /**
  * Convert string to double with strict parse error feedback.
  * @returns true if the entire string could be parsed as valid double,