Soroban: Add extendPersistentTtl Builtin Method

[tareknaser]

This PR adds support for extendPersistentTtl() method in Soroban, along with a test and documentation. Also, the Soroban testing infrastructure has been refactored to allow more flexible environment manipulation.

Documentation for extend_ttl
Fixes #1669

Changes

• Added support for extendPersistentTtl as a method on uint64 for the Soroban target.
  • In the Soroban SDK, extend_ttl is a generic function (IntoVal<Env, Val>)

pub fn extend_ttl<K>(&self, key: &K, threshold: u32, extend_to: u32)
where
    K: IntoVal<Env, Val>,

but Solidity does not support that, so it's implemented as a method instead.

• One assertion in the different_storage_types test is affected due to changes in diagnostic capture. A follow-up PR will address this.