feat: use eAPI session mechanism instead of BasicAuth

[mtache]

Replace BasicAuth authentication by using the eAPI Session Mechanism.

See eAPI Explorer -> Usage -> Cookies.

Some systems use 2-factor authentication where RSA is implemented and keys rotate every 30 seconds. It is cumbersome to authenticate using username and password in these systems. Command API requests use basic authentication by default. This results in high overhead on the switch to verify user credentials for each command request. HTTP sessions can be used to reduce the overhead in the above use cases by caching user authentication.