[Config CLI Parity] add squash to config structure tags to make decoding easier

[ashmeenkaur]

Description

Add "squash" to config structure tags to make decoding easier from legacy flagStorage & mountConfig.
This is a temporary change to make transition easier to new CLI and config flags and will be reverted post transition.
Reason to revert this in future - This change doesn't allow having leaf config with conflicting names.

Reference: https://pkg.go.dev/github.com/mitchellh/mapstructure#hdr-Embedded_Structs_and_Squashing
Open issue on mapstructure library which is blocking the change: mitchellh/mapstructure#356

Link to the issue in case of a bug fix.

NA

Testing details

1. Manual - Manually verified that viper configs and cobra flags are still working as intended
2. Unit tests - NA
3. Integration tests - NA

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 55 lines in your changes missing coverage. Please review.

Project coverage is 71.52%. Comparing base (52b1e10) to head (bac27e3).

Files	Patch %	Lines
cfg/config.go	0.00%	55 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2044      +/-   ##
==========================================
+ Coverage   71.46%   71.52%   +0.06%     
==========================================
  Files          99       99              
  Lines       10800    10800              
==========================================
+ Hits         7718     7725       +7     
+ Misses       2735     2728       -7     
  Partials      347      347              

Flag	Coverage Δ
unittests	71.52% <0.00%> (+0.06%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

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

[kislaykishore]

Please verify that the logic works for two levels of nesting. As per this, if a structure is not nested, that's when we can include the embedded struct to the tag value. It doesn't explicitly talk about the case where the struct is nested.

[ashmeenkaur]

s not nested, that's when we can include the embedded struct to the tag value. It doesn't explicitly talk about the case where the struct is nested.

Verified that it is working for nested structs too

[raj-prince]

Relying on Kislay's review.