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 moves almost all of the template functions into separate
packages under tpl/ and adds a namespace framework. All changes should
be backward compatible for end users, as all existing function names in
the template funcMap are left intact.
Seq and DoArithmatic have been moved out of the helpers package and into
template namespaces.
Most of the tests involved have been refactored, and many new tests have
been written. There's still work to do, but this is a big improvement.
I got a little overzealous and added some new functions along the way:
- strings.Contains
- strings.ContainsAny
- strings.HasSuffix
- strings.TrimPrefix
- strings.TrimSuffix
Documentation is forthcoming.
Fixes#3042
