Add replace and replaceAll functions to String

[darkdrag00nv2]

Issue to be solved

Add replace and replaceAll instance functions to Cadence.

1. replace(_ of: String, _ with: String): String: Returns a new String after replacing first occurrence of of with with.
2. replaceAll(_ of: String, _ with: String): String: Returns a new String after replacing all occurrences of of with with.

Epic: #1972

Suggested Solution

No response

[turbolent]

replaceAll was added in #2814. We can add e.g. a replaceFirst when there is demand.