Major update to reduce indexing time and other enhancements and bug fixes

Major update to reduce indexing time and other enhancements.

Enhancements:

• Add first, last and previous links to search and genres feeds
• Add books totals to language choose page
• Add file queue for parallel FB2 archives parsing
• Add documentation site
• Refine authors parsing
• Add simple check for book duplicates
• Refactor scan to parallel queue processing
• Add precompile statements
• Add command line data directory parameter
• Change xml decode for token stream parsing
• Use mime type "application/fb2+zip" in fb2 acquisition links
• Enhance OPDS feed localization
• Refine full text search query

Bug fixes:

• Add UTF-16 books indexing
• Check if service is in interactive mode
• Fix feed page size
• Deduplicate book genres when parsing
• Fix bug in GetCoverImage
• Fix empty plots by replacing buggy StripHTMLTags
• Close zip.ReadCloser
• Fix bug in authors sort name composing
• Change zip Store method for Deflate
• Close opened EPUB file
• Fix STOCK folder permissions #22
• Fix typos

Other:

• Tune logs verbosity
• Change log verbosity for zip parsing
• Make verbosity level case insensitive
• Fix usage help
• Update dependent package versions
• Upgrade Go version
• Clear old commented retentions in commented
• Clear feeds IDs
• Remove redundant SYNC structure