Add-on dependency updates with SSL 3 for Widows

[phunkyfish]

This update mostly all dependencies to latest versions, two now includes cmake and no more needs separated between POSIX and Windows.

As following steps comes to change to SSL 3.0.

v21.2.1

• Update dependency xz-utils to version 5.4.3
• Update dependency zlib to version 1.2.13
• Update dependency libxml2 to version 2.11.4
• Update dependency nettle to version 3.9
• Update dependency libpng to version 1.6.39
• Update dependency libzvbi to version 0.2.41
• Update dependency libiconv to version 1.17
• Update dependency gnutls to version 3.8.0
• Update dependency strawberry perl to version 5.32.1.1 (about Windows builds)
• Update dependency openssl to version 3.1.1 (about Windows builds)
• Cleanup dependency builds to use only "depends/common" source folder