feat: omit anonymous embedded struct

[abemedia]

Fixes Or Enhances

This PR adds an option to omit the names of anonymous embedded structs.

For example right now the code below would produce a namespace of Foo.Bar.Baz, with this code the option WithOmitAnonymousName would instead display Foo.Baz.

type Foo struct {
  Bar
}

type Bar struct {
  Baz string `validate:"required"`
}

• Fixes Method Struct(...) forms keys for embedded structures incorrectly #776

I'm not that familiar with the inner workings of validator so apologies if this is implemented in a terrible way. Happy to change it if the concept is acceptable and I get some pointers.

Make sure that you've checked the boxes below before you submit PR:

• Tests exist or have been written that cover this particular change.

@go-playground/validator-maintainers

[coveralls]

coverage: 73.896% (-0.007%) from 73.903%
when pulling 80db7ad on abemedia:feat/omit-anonymous-embedded-struct
into 84254ae on go-playground:master.

[abemedia]

@deankarn any chance of getting this in?
If the approach using an option is not preferable I'm also happy to implement an alternative approach, for example having an inline tag the way the stdlib does for JSON.