Fail when the builder can't load its configuration.

[jpeach]

Description:

If the builder can't load its build configuration file, it logs an error
and continues. This results in building a collector that is not the one
the user specified. Exit with a fatal error instead.

Link to tracking Issue:

None.

Testing:

$ ./builder
2022-07-22T11:32:21.845+1000	INFO	internal/command.go:85	OpenTelemetry Collector distribution builder	{"version": "dev", "date": "unknown"}
2022-07-22T11:32:21.845+1000	FATAL	internal/command.go:93	failed to load config file	{"config-file": "$HOME/.otelcol-builder.yaml", "error": "open $HOME/.otelcol-builder.yaml: no such file or directory"}
go.opentelemetry.io/collector/cmd/builder/internal.initConfig
	/Users/jpeach/upstream/opentelemetry/opentelemetry-collector/cmd/builder/internal/command.go:93
go.opentelemetry.io/collector/cmd/builder/internal.Command.func1
	/Users/jpeach/upstream/opentelemetry/opentelemetry-collector/cmd/builder/internal/command.go:44
github.com/spf13/cobra.(*Command).execute
	/Users/jpeach/go/pkg/mod/github.com/spf13/cobra@v1.5.0/command.go:872
github.com/spf13/cobra.(*Command).ExecuteC
	/Users/jpeach/go/pkg/mod/github.com/spf13/cobra@v1.5.0/command.go:990
github.com/spf13/cobra.(*Command).Execute
	/Users/jpeach/go/pkg/mod/github.com/spf13/cobra@v1.5.0/command.go:918
main.main
	/Users/jpeach/upstream/opentelemetry/opentelemetry-collector/cmd/builder/main.go:26
runtime.main
	/opt/homebrew/Cellar/go/1.18.4/libexec/src/runtime/proc.go:250
$ echo $?
1

[codecov]

Codecov Report

Merging #5731 (652a662) into main (3e14ee9) will decrease coverage by 0.03%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #5731      +/-   ##
==========================================
- Coverage   91.56%   91.53%   -0.04%     
==========================================
  Files         192      192              
  Lines       11411    11411              
==========================================
- Hits        10449    10445       -4     
- Misses        768      771       +3     
- Partials      194      195       +1     

Impacted Files	Coverage Δ
pdata/internal/common.go	91.85% <0.00%> (-0.75%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 3e14ee9...652a662. Read the comment docs.

[bogdandrutu]

not relevant to the PR: I remember that I've seen an issue with errors in the collector being printed twice, I feel that this was the issue.