Convert ezbake to use junction-api types.

[blinsay]

Use junction-api types for xDS and kube conversions, which means that pushing dynamic config can now be done with junction-client dumping kube yaml.

This ezbake passes smoke tests, but definitely have problems with xDS resource names not being, since we don't take service ports into account. Since we're still passing smoke tests and this enables dynamic config, I'm going to push it.

After this comes a quick sequence of follow-up PRs to:

• Add resource name mappings to junction-api and support for generating/parsing unique xdstp:// URLs for any Target.
• Switch to using those names in ezbake, for both xDS on the wire and internal caching. No more collisions!
• Switch junction-client to expecting and parsing xdstp:// URLs off the wire to figure out target data.

[blinsay]

I bumped MSRV to 1.79 to match junction-client. We got a CI failure testing on 1.76 because junction-client takes advantage of some temporary lifetime extension stuff that got added in 1.79.