We have been using `go-toml` for language files only. This commit makes it the only TOML library.
It's spec compliant and very fast.
A benchark building a site with 200 pages with TOML front matter:
```bash
name old time/op new time/op delta
SiteNew/Regular_TOML_front_matter-16 48.5ms ± 1% 47.1ms ± 1% -2.85% (p=0.029 n=4+4)
name old alloc/op new alloc/op delta
SiteNew/Regular_TOML_front_matter-16 16.9MB ± 0% 16.7MB ± 0% -1.56% (p=0.029 n=4+4)
name old allocs/op new allocs/op delta
SiteNew/Regular_TOML_front_matter-16 302k ± 0% 296k ± 0% -2.20% (p=0.029 n=4+4)
```
Note that the front matter unmarshaling is only a small part of building a site, so the above is very good.
Fixes#8801
This commit started out investigating a `concurrent map read write` issue, ending by replacing the map with a struct.
This is easier to reason about, and it's more effective:
```
name old time/op new time/op delta
SiteNew/Regular_Deep_content_tree-16 71.5ms ± 3% 69.4ms ± 5% ~ (p=0.200 n=4+4)
name old alloc/op new alloc/op delta
SiteNew/Regular_Deep_content_tree-16 29.7MB ± 0% 27.9MB ± 0% -5.82% (p=0.029 n=4+4)
name old allocs/op new allocs/op delta
SiteNew/Regular_Deep_content_tree-16 313k ± 0% 303k ± 0% -3.35% (p=0.029 n=4+4)
```
See #8749
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
Add Scratch.DeleteInMap method. This method works similar to Scratch.SetInMap. It takes in two string parameters, key and mapKey and deletes the value mapped to mapKey in key
Closes#8504
* Change version string format as proposed by @moorereason
1. shorten program name
2. make version string semver compliant with +extended.
The slash is not allowed in semver.
3. Use key=value pairs for BuildDate etc.
* Add optional vendorInfo to version string
to help with issue triaging, e.g. VendorInfo=debian:0.80.0-7
