Added support for port prefix regex

[itamar-talmon]

What I did
Removed the dependency on the "Ethernet" string in the SONiC code base and added support
for extending the front panel port name pattern.

How I did it

Introduced FRONT_PANEL_PORT_PREFIX_REGEX that extends the old FRONT_PANEL_PORT_PREFIX ("Ethernet")
Updated all the relevant usage of the "Ethernet" throughout the code base to use the new regex pattern
How to verify it
Pass all UT and CI testing.

Why I did it
In order to support distinguishing between different types of front panel ports in a maintainable fashion.
Specifically, we are planning to bring up a system with 'service' ports (in addition to the regular ethernet data ports) - these
are lower speed ports that used for connection to accelerators, internal loopbacks and more.

- Related Commits and Merge Strategy
This is part of a group of related commits and should be merged after sonic-net/sonic-swss-common#598 and sonic-net/sonic-buildimage#10471 and sonic-net/sonic-py-swsssdk#121.

The full merge order is:

1. swss-common - Added front panel port prefix regex to schema.h sonic-swss-common#598
2. sonic-buildimage - Added support for front panel port prefix regex sonic-buildimage#10471
3. swsssdk - Added support for front panel port prefix regex sonic-py-swsssdk#121
4. all the rest
   https://github.com/Azure/sonic-utilities/pull/2127
   https://github.com/Azure/sonic-snmpagent/pull/251
   https://github.com/Azure/sonic-swss/pull/2223
   https://github.com/Azure/sonic-platform-daemons/pull/252
   https://github.com/Azure/sonic-platform-common/pull/274

[itamar-talmon]

This PR depends on sonic-net/sonic-swss-common#598 so it will not pass until it merged

[prgeor]

@itamar-talmon unit tests are failing

[itamar-talmon]

@kcudnik @qiluo-msft - could you please check it out after my update?
Checks will fail until related commits will be merged (in the description).
Thank you!

[prgeor]

Quoting @lguohan here:-

the overall motivation is not quite clear. can you describe what are you trying to achieve here? here is the sonic port naming convention. for new port names convention to be introduced, we need to make a proposal first here. https://github.com/sonic-net/SONiC/blob/master/doc/sonic-port-name.md