fix(template-lib)!: improve initial supply api resource builder

Description

Improve API for resource builder with initial supply. Rename XTR2 constant to XTR Add Bucket::join

Motivation and Context

Previously if you provided an initial supply for the resource builder and called build() a panic would occur. This PR changes initial_supply to immediately build and return the bucket preventing the user from making the above error at compile time.

Previous API:

let bucket = ResourceBuilder::fungible().initial_supply(1000).build_bucket()

// will panic at runtime
let bucket = ResourceBuilder::fungible().build_bucket()

New API:

let bucket = ResourceBuilder::fungible().initial_supply(1000);

let bucket = ResourceBuilder::non_fungible()
       .initial_supply((1..=100).map(NonFungibleId::from_u32));

let confidential = ResourceBuilder::confidential()
       .initial_supply(confidential_supply);

How Has This Been Tested?

Existing engine tests updated

What process can a PR reviewer use to test or verify this change?

Update existing templates to use the new API

Breaking Changes

[ ] None
[ ] Requires data directory to be deleted
[x] Other - Please specify

BREAKING CHANGE: templates that previously built resources with initial supply will no longer compile. The ABI for buckets adds Join. Since the integer representation of the ops shifts by 1 after Join some bucket operations will be invalid on previous WASM. i.e. WASM needs to be recompiled.

tari-project / tari-dan