* Add file context to minifier errors when publishing
* Misc fixes (see issues)
* Allow custom server error template in layouts/server/error.html
To get to this, this commit also cleans up and simplifies the code surrounding errors and files. This also removes the usage of `github.com/pkg/errors`, mostly because of https://github.com/pkg/errors/issues/223 -- but also because most of this is now built-in to Go.
Fixes#9852Fixes#9857Fixes#9863
During Hugo deploy when a remote MD5 is invalid (e.g due to multipart eTag) Hugo reads the entire remote file and calculates the MD5 again which can be slow.
This commit updates the file upload so that it will also store an MD5 hash in the cloud provider's attributes. e.g in AWS this looks like x-amz-meta-md5chksum: 26fe392386a8123bf8956a16e08cb841.
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
So we can use it and output.Format as map key etc.
This commit also fixes the media.Type implementation so it does not need to mutate itself to handle different suffixes for the same MIME type, e.g. jpg vs. jpeg.
This means that there are no Suffix or FullSuffix on media.Type anymore.
Fixes#8317Fixes#8324
Currently, if cache invalidation is enabled when running `hugo deploy --dryRun` with , the deployer does not take the dry run flag into consideration and triggers CloudFront/GoogleCloudCDN cache invalidation if any of those services are configured.
This change will instead print a feedback message if a dry run is in effect and quiet mode is not enabled.
Fixes#7884
