Builds with PGO enabled

[fbac]

Priority: Low

Golang applications can be optimized by compiling them using pprof profiles, via PGO, such as in go build -pgo=profiles.pprof ...

Ideally, the pprof profiles are gathered from representative (production) environments and used in future builds. Several profiles can be merged into one and passed to pgo.

This task should be divided into multiple sub-tasks!