Move the watch timer out of `authority` and into `transport`

[easwars]

Resource watch timer is a stream level concept in C-core, and helps them deal with a race mentioned here much more easily than our implementation where the watch timer is part of the resource state in the authority.

For more details about the C-core implementation, see here.

[dfawley]

@easwars is this still relevant?

[easwars]

The resource watch timer has been moved into the ADS stream implementation as part of one of the many refactors. So, this is not relevant anymore.