Unify environment creation under create command

[SarthakJariwala]

Currently, create command can create new environment for two conditions:

New environment from scratch

$ ezconda create --name env

From environment specifications file (yml file)

$ ezconda create --file env.yml

---

Another condition - creating from lock file - is currently achieved using recreate method, which may lead to confusion for users.

This proposal will move creating environment from lock file also using create method and deprecate recreate method.

From environment lock file (proposed)

$ ezconda create --file env-darwin-x86_64.lock