Move EZSP send lock from EZSP to individual protocol handlers

[puddly]

We recently moved a lot of code into individual EZSP protocol handlers. This introduced a "hole" where protocol handlers could run multiple commands at once within a single semaphore.

This PR moves the semaphore into the protocol handlers, closing this hole. I've also adjusted protocol timeouts to better handle TCP failures, making communication with TCP coordinators a bit more resilient. I think after this PR we may be able to immediately disconnect on watchdog failure as opposed to allowing up to five to fail.

CC @tube0013

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.14%. Comparing base (e160be2) to head (9f6f286).
Report is 1 commits behind head on dev.

Additional details and impacted files

@@           Coverage Diff           @@
##              dev     #649   +/-   ##
=======================================
  Coverage   99.13%   99.14%           
=======================================
  Files          50       50           
  Lines        3486     3494    +8     
=======================================
+ Hits         3456     3464    +8     
  Misses         30       30           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.