BaseTools: Scripts/efi_gdb.py: Add gdb EFI commands and pretty Print

BaseTools: Scripts/efi_gdb.py: Add gdb EFI commands and pretty Print

https://bugzilla.tianocore.org/show_bug.cgi?id=3500

Use efi_debugging.py Python Classes to implement EFI gdb commands:
(gdb) help efi
Commands for debugging EFI. efi <cmd>

List of efi subcommands:

efi devicepath -- Display an EFI device path.
efi guid -- Display info about EFI GUID's.
efi hob -- Dump EFI HOBs. Type 'hob -h' for more info.
efi symbols -- Load Symbols for EFI. Type 'efi_symbols -h' for more info.
efi table -- Dump EFI System Tables. Type 'table -h' for more info.

This module is coded against a generic gdb remote serial stub. It should
work with QEMU, JTAG debugger, or a generic EFI gdb remote serial stub.
No modifications of EFI is required to load symbols.

Example usage:
OvmfPkg/build.sh qemu -gdb tcp::9000
gdb -ex "target remote localhost:9000" -ex "source efi_gdb.py"

Cc: Leif Lindholm <quic_llindhol@quicinc.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Cc: Bob Feng <bob.c.feng@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Yuwei Chen <yuwei.chen@intel.com>
Signed-off-by: Rebecca Cran <quic_rcran@quicinc.com>
Reviewed-by: Bob Feng <bob.c.feng@intel.com>
Acked-by: Liming Gao <gaoliming@byosoft.com.cn>