Support a custom username and password with the deploy script

[samfreund]

Description

It's convenient to be able to run the deploy script with a custom username and password, if they happen to be different from the default. This PR also adds the ability to run the deploy task with a new UI build, using the withBuildAndCopyUI flag.

Meta

Merge checklist:

• Pull Request title is short, imperative summary of proposed changes
• The description documents the what and why
• If this PR changes behavior or adds a feature, user documentation is updated
• If this PR touches photon-serde, all messages have been regenerated and hashes have not changed unexpectedly
• If this PR touches configuration, this is backwards compatible with settings back to v2024.3.1
• If this PR touches pipeline settings or anything related to data exchange, the frontend typing is updated
• If this PR addresses a bug, a regression test for it is added