net/boinc-client: Update 8.2.4 => 8.2.8

Changelogs:

• https://github.com/BOINC/boinc/releases/tag/client_release%2F8.2%2F8.2.5
• https://github.com/BOINC/boinc/releases/tag/client_release%2F8.2%2F8.2.6
• https://github.com/BOINC/boinc/releases/tag/client_release%2F8.2%2F8.2.7
• https://github.com/BOINC/boinc/releases/tag/client_release%2F8.2%2F8.2.8
• https://github.com/BOINC/boinc/compare/client_release/8.2/8.2.4...client_release/8.2/8.2.5
• https://github.com/BOINC/boinc/compare/client_release/8.2/8.2.5...client_release/8.2/8.2.6
• https://github.com/BOINC/boinc/compare/client_release/8.2/8.2.6...client_release/8.2/8.2.7
• https://github.com/BOINC/boinc/compare/client_release/8.2/8.2.7...client_release/8.2/8.2.8

• Clarify LICENSE
• Add LICENSE_FILE
• Use dynamic SOVERSION
• Headers conflict with archivers/libzip now resolved in upstream
• Rename loop variable for pixmaps from 'name' to 'size' for clarity
• Pet portclippy(1) and portfmt(1)

Approved by: db@, yuri@ (Mentors, implicit)
Differential Revision: https://reviews.freebsd.org/D54302