Optimize reboot times by disabling default initialization and startup of certain L2 applications

When rebooting the device, the Layer 2 (L2) applications l2ald, l2ald-agent, l2cpd, and l2cpd-agent are initialized and started only if any of the following configuration hierarchy levels contain any configuration statements: 

• [edit interface interface-name unit number family ethernet-switching] 
  
• [edit vlans] 
• [edit routing-instance instance-name instance-type virtual-switch] 
• [edit routing-instance instance-name instance-type mac-vrf] 
• [edit protocols l2-learning] 

Additionally, l2cpd, and l2cpd-agent are initialized and started if the [edit protocols lldp] hierarchy level contains any configuration statements.

 As a result of this change, if your configuration already contains these configuration statements and you then delete all of them, these L2 applications stop running.