aemfvp-rme: script updates for 23'q4 release

The 23'q4 release of aemfvp-a-rme software stack migrates the quality
level of stack to EAC5. There are changes in model-script as part of
this migration as follows :

- TF build flags for GIC extended SPI ranges.
- enabling SVE plugins to model.
- enabling Automated runs for fvp in docker environment.
- dynamically choosing FVP path from host arch.
- added function capture_terminal_output to flush out xterm output in case of
  automated runs.
- ssh_connection.sh test script for checking ssh to realm guest from host.

Signed-off-by: Nitin Sharma <nitin.sharma3@arm.com>
Change-Id: I7f002ee01315dd931484b7c6880cbc955f922cb8