Add permission 'manage protected forms'

This adds a new permissions 'manage protected forms' that allows access to the configuration page in addition to the broader 'administer site configuration' permission.

Closes #3291212

config/install/protected_forms.settings.yml

-protected_forms:
-  allowed_scripts:
-    - Latin
-  check_quantity: 50
-  reject_message: 'Oops! It looks like your post contains spam content. If you believe otherwise, please contact us. We apologize for the inconvenience.'
-  langcode: 'en'
-  reject_patterns: "http://, https://, www, ftp://, mailto:, smb://, afp://, file://, gopher://, news://, ssl://, sslv2://, sslv3://, tls://, tcp://, udp://, url=, href=\ndating, sex, porn, fuck, free, win, buy, captcha, spam, hello. and bye., mail.ru, reading this message, reading my message, reading through my message, are whitelisted, great website, late client, ciao a tutti, viagra, cheap, casino, advertising, keyword, promotion, porntubered,     :,    :, ps: how are you?, beautiful models, privet, beautiful girls, best girls, dosug, trustable, look at the, v7bomdefex, what is it -, email marketing, read your site"
-  log_rejected: 0