Introduce node id to identify pageservers (other services)

[LizardWizzard]

Sometimes it is desirable to distinguish between different instances of a particular service, connection string may be used for that but it is unstable because one service may have more than one address e.g when accessed from different networks/have multiple domain names associated with it.

Safekeepers are currently in progress of gaining this feature (#1081) but it is needed for other services too. I believe that It is beneficial to implement it in some unified way somewhere in zenith_utils.

ref #886

[kelvich]

+1

[hlinnaka]

For pageservers: #1310