Fix lint warnings.

[hulto]

What type of PR is this?

/kind cleanup

What this PR does / why we need it:

Cleans up most of the compiler warnings with the exception of windows specific unused vars and const_frozen_string in the insert_dict_kv.

Which issue(s) this PR fixes:

Fixes #451

[codecov]

Codecov Report

Attention: 128 lines in your changes are missing coverage. Please review.

Comparison is base (3306759) 71.55% compared to head (b8476ea) 71.82%.

Files	Patch %	Lines
implants/lib/eldritch/src/file/find_impl.rs	0.00%	60 Missing ⚠️
implants/imix/src/main.rs	0.00%	25 Missing ⚠️
implants/imix/src/init.rs	12.50%	14 Missing ⚠️
...mplants/lib/eldritch/src/sys/write_reg_hex_impl.rs	93.79%	8 Missing ⚠️
...mplants/lib/eldritch/src/sys/write_reg_int_impl.rs	93.79%	8 Missing ⚠️
...mplants/lib/eldritch/src/sys/write_reg_str_impl.rs	93.79%	8 Missing ⚠️
implants/imix/src/tasks.rs	0.00%	4 Missing ⚠️
implants/imix/src/install.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #455      +/-   ##
==========================================
+ Coverage   71.55%   71.82%   +0.27%     
==========================================
  Files         118      118              
  Lines        9013     9302     +289     
==========================================
+ Hits         6449     6681     +232     
- Misses       2441     2498      +57     
  Partials      123      123              

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