Change modem preset shortcuts to not request channels, and to request remote config when needed

[ianmcorvidae]

Fixes #662

This should change the --ch-<preset> commands to behave equivalently to --set lora.modem_preset <preset>

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 5 lines in your changes missing coverage. Please review.

Project coverage is 61.44%. Comparing base (aa6f096) to head (8ba92da).
Report is 41 commits behind head on master.

Files with missing lines	Patch %	Lines
meshtastic/__main__.py	0.00%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #668      +/-   ##
==========================================
- Coverage   61.48%   61.44%   -0.04%     
==========================================
  Files          24       24              
  Lines        3593     3595       +2     
==========================================
  Hits         2209     2209              
- Misses       1384     1386       +2     

Flag	Coverage Δ
unittests	61.44% <0.00%> (-0.04%)	⬇️

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.