Add units for duration value

[jcamiel]

Duration value is Hurl format are sometimes milliseconds, (--delay) or seconds (--max-time). It would increase the readibility of Hurl format if we could optionally specify a time unit:

Without time unit:

GET https://foo.com
[Options]
delay: 2000
max-time: 60
HTTP 200

POST https://foo.com
[Options]
retry-interval: 100
HTTP 200
[Asserts]
duration < 1000

With time unit:

GET https://foo.com
[Options]
delay: 2s
max-time: 60s
HTTP 200

POST https://foo.com
[Options]
retry-interval: 100ms
HTTP 200
[Asserts]
duration < 1s

Question: do we want to support this with command line values ?