[FEATURE] Run-length encoding

[Turtel216]

Feature Description

Please provide a brief description of the feature you would like to see implemented.

Add a Run-length encoding and decoding function to the strings module.

---

Use Case

Describe the use case for this feature. Why would it be beneficial to have this functionality?

Useful for lossless compression of strings with repeating characters, i.e. aaabbb -> 3a3b

---

Pseudo Code

RunLengthEncode

func main() {
	encoded := strings.RunLengthEncode("aaabbbccc")
	fmt.Println(encoded) // Output: 3a3b3c
}

RunLengthDecode

func main() {
	decoded := strings.RunLengthDecode("3a3b3c")
	fmt.Println(decoded) // Output: aaabbbccc
}