[breaking] Remove gRPC settings service

[cmaglie]

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• The PR has no duplicates (please search among the Pull Requests
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• The PR follows
  our contributing guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)
• UPGRADING.md has been updated with a migration guide (for breaking changes)
• configuration.schema.json updated if new parameters are added.

What kind of change does this PR introduce?

Removes the gRPC settings service, and migrates the RPC calls to the command service.
The service cc.arduino.cli.settings.v1 no longer exists and all existing RPC calls have been moved to the
cc.arduino.cli.commands.v1 service adding a Settings prefix to the names of all messages. The existing RPC calls:

• rpc GetAll(GetAllRequest) returns (GetAllResponse)
• rpc Merge(MergeRequest) returns (MergeResponse)
• rpc GetValue(GetValueRequest) returns (GetValueResponse)
• rpc SetValue(SetValueRequest) returns (SetValueResponse)
• rpc Write(WriteRequest) returns (WriteResponse)
• rpc Delete(DeleteRequest) returns (DeleteResponse)

are now renamed to:

• rpc SettingsGetAll(SettingsGetAllRequest) returns (SettingsGetAllResponse)
• rpc SettingsMerge(SettingsMergeRequest) returns (SettingsMergeResponse)
• rpc SettingsGetValue(SettingsGetValueRequest) returns (SettingsGetValueResponse)
• rpc SettingsSetValue(SettingsSetValueRequest) returns (SettingsSetValueResponse)
• rpc SettingsWrite(SettingsWriteRequest) returns (SettingsWriteResponse)
• rpc SettingsDelete(SettingsDeleteRequest) returns (SettingsDeleteResponse)

What is the current behavior?

No change

What is the new behavior?

No change

Does this PR introduce a breaking change, and is titled accordingly?

Yes.

Other information

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (c45ab20) 64.80% compared to head (9f5eab4) 64.81%.
Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #2411   +/-   ##
=======================================
  Coverage   64.80%   64.81%           
=======================================
  Files         207      207           
  Lines       20153    20150    -3     
=======================================
  Hits        13060    13060           
+ Misses       5978     5976    -2     
+ Partials     1115     1114    -1     

Flag	Coverage Δ
unit	64.81% <100.00%> (+<0.01%)	⬆️

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

Files	Coverage Δ
commands/daemon/settings.go	92.78% <100.00%> (ø)
internal/cli/config/delete.go	88.88% <100.00%> (ø)
internal/cli/daemon/daemon.go	46.93% <ø> (-1.58%)	⬇️

... and 1 file with indirect coverage changes

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