Converted all memset() deletions to conventional clearing methods

[delta1513]

Fixes #3245

Description of the Change
The memset() function is used to delete certain structs by overwriting them with zeroes, this can be unsafe and causes the compiler to complain with a warning.

This was solved by replacing memsets with empty struct initialisers where possible. There were some instances where this was being overwritten, and in this case, I had to create clear() methods in each of the structs that had these memsets.

Notes:

• I took the liberty to do some garbage collection in one of the clear() functions, namely APP_VERSION::clear() in gui_rpc_client_ops.cpp. Just a heads-up in-case this is bad, but I saw only good in doing this considering the previous implementation simply made the ptr = 0.
• It looks like my editor may have messed with some of the spaces and tabs.
• This is my first PR so feedback is appreciated!

Alternate Designs
N/A

Release Notes
Removed all object deletions using memset() and created conventional clearing functions

[codecov]

Codecov Report

Merging #3363 into master will not change coverage.
The diff coverage is 0%.

@@          Coverage Diff           @@
##           master   #3363   +/-   ##
======================================
  Coverage    9.27%   9.27%           
======================================
  Files          36      36           
  Lines        5992    5992           
======================================
  Hits          556     556           
  Misses       5436    5436

Impacted Files	Coverage Δ
lib/coproc.h	0% <0%> (ø)	⬆️

[davidpanderson]

I'm going to do this a different way, as described here:
https://stackoverflow.com/questions/6891720/initialize-reset-struct-to-zero-null

[AenBleidd]

Closing in favor of #3364