Builder pattern for constructing Link

[swanandx]

Support for constructing LinkRx/LinkTx using LinkBuidler.

let (link_tx, link_rx, notification) = LinkBuilder::new(&client_id, router_tx)
    .tenant_id(tenant_id) // None by default
    .clean_session(clean_session) // true by default
    .last_will(lastwill) // None by default
    .dynamic_filters(dynamic_filters) // false by default
    .topic_alias_max(topic_alias_max) // 0 by default
    .build()?;

Type of change

Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• Formatted with cargo fmt
• Make an entry to CHANGELOG.md if its relevant of user of the library. If its not relevant mention why.

[mnpw]

LGMT, thanks 🚀🚀🚀

please merge after addressing the comments