## Changes
This diagnostics type allows us to capture multiple warnings as well as
errors in the return value. This is a preparation for returning
additional warnings from mutators in case we detect non-fatal problems.
* All return statements that previously returned an error now return
`diag.FromErr`
* All return statements that previously returned `fmt.Errorf` now return
`diag.Errorf`
* All `err != nil` checks now use `diags.HasError()` or `diags.Error()`
## Tests
* Existing tests pass.
* I confirmed no call site under `./bundle` or `./cmd/bundle` uses
`errors.Is` on the return value from mutators. This is relevant because
we cannot wrap errors with `%w` when calling `diag.Errorf` (like
`fmt.Errorf`; context in https://github.com/golang/go/issues/47641).
## Changes
Before this PR we would load all yaml files matching * and \*/\*.yml
files as bundle configurations. This was problematic since this would
also load yaml files that were not meant to be a part of the bundle
## Tests
Manually, now files are no longer included unless manually specified
## Changes
Fixed error reporting when included invalid files in include section
Case 1. When the file to include is invalid, throw an error
Case 2. When the file is loaded but the schema is wrong, indicate which
file is failed to load
## Tests
With non-existent notexists.yml
```
databricks bundle deploy
Error: notexists.yml defined in 'include' section does not match any files
```
With malformed notexists.yml
```
databricks bundle deploy
Error: failed to load /Users/andrew.nester/dabs/wheel/notexists.yml: error unmarshaling JSON: json: cannot unmarshal string into Go value of type config.Root
```
Pieter Noordhuis
shreyas-goenka
Andrew Nester