The main motivation behind this is simplicity and correctnes, but the new small config library is also faster:
```
BenchmarkDefaultConfigProvider/Viper-16 252418 4546 ns/op 2720 B/op 30 allocs/op
BenchmarkDefaultConfigProvider/Custom-16 450756 2651 ns/op 1008 B/op 6 allocs/op
```
Fixes#8633Fixes#8618Fixes#8630
Updates #8591Closes#6680Closes#5192
This commit fixes some issues where modules in /assets share the same name as in node_modules.
This was not intended, and with this commit the node_modules-components should be isolated. If you want to redefine something inside node_modules, use the `defines` option.
Fixes#7948
Updates #7777
Added support to allow SourceMap files to be external to the build.
In addition added more information when the js compilation has an error.
Correctly append sourceMappingURL to output file.
Fix merge conflict.
Added a flag to allow turning on sourcemap in ESBuild. The current support
can only support inline or true as value for sourcemap. This is because
the way ESBuild is invoked it doesn't have a separate output path
to write the mapfile external to the asset pipeline. Add disable for "" and "0".
Add test script and make sure mage check passes.
Fixes#7607
