Update remote mmap, avoid page faults using madvise syscall. Remove l…

[RonFed]

WIP

• Update remote mmap, avoid page faults using madvise syscall
• Remove large local variable in uprobe_HttpClient_Do to avoid reaching the 512 bytes limit of eBPF

[edeNFed]

Adding some more context on this:
We observed at some Keyval customers that when the machine is lacking resources (especially memory), Linux would free the memory area used for context propagation which will cause bpf_write_user to fail. This should fix this scenario

[MrAlias]

Please rebase these changes into internal/pkg (changed in #282). The pkg directory is going to be removed in #302 given that package is no longer used.

[RonFed]

Will be handled in #368