There were some issues introduced with the plural counting when we upgraded from v1 to v2 of go-i18n.
This commit improves that situation given the following rules:
* A single integer argument is used as plural count and passed to the i18n template as a int type with a `.Count` method. The latter is to preserve compability with v1.
* Else the plural count is either fetched from the `Count`/`count` field/method/map or from the value itself.
* Any data type is accepted, if it can be converted to an integer, that value is used.
The above means that you can now do pass a single integer and both of the below will work:
```
{{ . }} minutes to read
{{ .Count }} minutes to read
```
Fixes#8454Closes#7822
See https://github.com/gohugoio/hugoDocs/issues/1410
This change is mostly motivated to get a more stable CI build (we're building the Hugo site there, with Instagram and Twitter shortcodes sometimes failing).
Fixes#7866
