Fix unclosed tickers/timers

[farazdagi]

What type of PR is this?

Bug fix

What does this PR do? Why is it needed?

• Timers and tickers open channels, and to release associated resources must be stopped. So, this PR:
  • Adds Stop() calls whenever they are missing
  • In number of places moves (timer|ticker).Stop() method closer to object creation (invoking the stopping routing with defer). This is done as a more natural way to work with resources in Go: you allocate resources, and if you can, you immediately call defer releaseFn().

Which issues(s) does this PR fix?

N/A

Other notes for review

[codecov]

Codecov Report

Merging #7190 into master will increase coverage by 1.57%.
The diff coverage is 70.37%.

@@            Coverage Diff             @@
##           master    #7190      +/-   ##
==========================================
+ Coverage   60.07%   61.65%   +1.57%     
==========================================
  Files         323      410      +87     
  Lines       27422    32548    +5126     
==========================================
+ Hits        16473    20066    +3593     
- Misses       8733     9617     +884     
- Partials     2216     2865     +649