Align Percona Server RPM and DEB packaging with MySQL upstream

[EvgeniyPatlan]

Modernize RPM and DEB packaging infrastructure to align with MySQL 9.6.0
upstream patterns, improving maintainability, security, and feature parity.

RPM changes:

• Remove SysV init support, make systemd unconditional
• Drop EL6 compat libs (libmysqlclient.so.16 / MySQL 5.1.73)
• Replace custom filter-provides.sh/filter-requires.sh with modern __requires_exclude/__provides_exclude_from RPM macros
• Add Profile-Guided Optimization (PGO) build support
• Add libmysqlclient.so.21 compat for EL8/9, built from MySQL 8.0.37 source
• Create percona-server-client-plugins subpackage for auth plugins
• Factor telemetry setup into external helper scripts
• Convert @@var@@ shell substitution to CMake @var@ spec templating
• Create Docker/minimal spec variant (percona-server-minimal.spec.in)
• Update build-rpm.sh to use git instead of bzr

DEB changes:

• Upgrade debhelper compat level from 9 to 13
• Replace deprecated dh_systemd_enable/dh_installinit/dh_systemd_start with dh_installsystemd
• Consolidate 80+ individual dh_strip -X calls into prefix-based patterns
• Activate AppArmor integration (previously commented out)
• Create percona-server-client-plugins package
• Split into server-core/client-core and server/client wrapper packages
• Add meta packages (percona-server, percona-client, percona-testsuite)
• Add PGO build support via DEB_PGO=1 environment variable
• Switch zlib, LZ4, zstd from bundled to system libraries
• Factor telemetry into external helper scripts
• Remove monolithic percona-server-dbg in favor of auto-generated dbgsym
• Create rules.in template for CMake-based generation

Builder script (percona-server-9.0_builder.sh):

• Update spec generation to use .spec.in template with @var@ markers
• Remove call-home.sh wget/heredoc injection for both RPM and DEB
• Add telemetry helper script extraction for SRPM builds
• Remove EL6 devtoolset-8 references
• Use exact spec filename for tarball extraction