/country/add: prohibit repeated special characters

[php-coder]

Currently user can specify name with multiple spaces inside, for example test test. We should disallow it (probably just replacing them by one) and also add migration for that.

When user specifies the names of country during its creation, we should validate these names and prohibit the repetition of the hyphen (for example: te--st). Also we should add the converter that will replace two and more spaces into single.

Note that we should apply this conversion/validation to the both fields.

What should be done:

• Add integration tests
• Add validation (@Pattern will be helpful)

[php-coder]

This also relates to #442, #443 and #444 because each space gets replaces by hyphen and name looks different while their slug is the same. For example, a test != a test but they have the same slug a-test.

[php-coder]

We should transform multiple hyphens and underscores too.

[php-coder]

When we talked about replacing multiple spaces it sounded ok, but when we decided to replace hyphens and underscores too, it has changed the situation. Such implicitly behavior can puzzle user, especially with login field: user wishes to use foo__bar login, submitted the form but we modified the login to foo_bar. Now user tries to sign in with the login foo__bar and of course it wouldn't work.

To make the user experience more transparent let's add validation for it: show an error when field contains repeatable characters.

[php-coder]

and also add migration for that.

No-no-no. We can't do that because it will broke existing logins and also change URLs of some categories/countries (and they start to return 404 instead of do a redirection).