feat: "-S" flag customization improvements

[sultan-ov]

• improve/add definition and implementation of the following flags:
• -S, --blocksize: show size of allocated file system blocks
• -S, --allocated-size=(mode): list the allocated size of each file (bytes, blocks)
• --blocksize: list the allocated size of each file, in bytes (alias for --allocated-size=bytes)
• --blocks: list the allocated size of each file, in blocks (alias for --allocated-size=blocks)
• improve "eza_colors.5.md" - bl: "a file’s number of blocks" -> "a file’s allocated size, in blocks"
• improve bl color code applying (not applying in v0.23.4)