Remove deprecated source code

[anatol-sialitski]

Clean source code:

• Remove usage of portalRequest.getSite()
• Remove X-Guillotine-SiteKey header, the siteKey argument for guillotine field must be used instead
• Remove query and queryConnection fields for the HeadlessCms type
• Remove QueryContentConnection type
• Remove FilterInput, ExistsFilterInput, NotExistsFilterInput, HasValueFilterInput, IdsFilterInput and BooleanFilterInput
• Remove the type argument for pageUrl field of Content type
• Remove the type argument for _path field of Content type
• Remove type ContentPathType
• Replace type of the params argument for pageUrl, attachmentUrl, imageUrl, mediaUrl from String to JSON