[Provider] Improve output of `provider show` command

Registering provider gives this helpful hint:

(env) D:\git\azure-cli [usages ≡]> az provider register -n Microsoft.Sql
Registering is still on-going. You can monitor using 'az provider show -n Microsoft.Sql'

However the output of az provider show -n Microsoft.Sql is huge and overwhelming. az provider show -n Microsoft.Sql --query registrationState would be better.

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Environment summary

Install Method: How did you install the CLI? (e.g. pip, interactive script, apt-get, Docker, MSI, nightly)
Answer here: nightly

CLI Version: What version of the CLI and modules are installed? (Use az --version)
Answer here:

azure-cli (2.0.3+dev)

acr (2.0.1+dev)
acs (2.0.3+dev)
appservice (0.1.3+dev)
batch (2.0.1+dev)
cloud (2.0.1+dev)
component (2.0.1+dev)
configure (2.0.3+dev)
container (0.1.3+dev)
core (2.0.3+dev)
dla (0.0.2+dev)
dls (0.0.2+dev)
documentdb (0.1.3+dev)
feedback (2.0.1+dev)
find (0.0.2+dev)
iot (0.1.3+dev)
keyvault (2.0.1+dev)
lab (0.0.2+dev)
monitor (0.0.2+dev)
network (2.0.3+dev)
nspkg (2.0.0+dev)
profile (2.0.3+dev)
redis (0.2.0+dev)
resource (2.0.3+dev)
role (2.0.2+dev)
sql (2.0.1+dev)
storage (2.0.3+dev)
taskhelp (0.1.1b4+dev)
testsdk (0.1.0+dev)
utility-automation (0.1.1)
vm (2.0.3+dev)

Python (Windows) 3.5.3 (v3.5.3:1880cb95a742, Jan 16 2017, 16:02:32) [MSC v.1900 64 bit (AMD64)]

OS Version: What OS and version are you using?
Answer here: Windows 10

Shell Type: What shell are you using? (e.g. bash, cmd.exe, Bash on Windows)
Answer here: PowerShell

[lmazuel]

It’s even part of msrestazure since 0.4.9, and less than less needed 😃

[yugangw-msft]

 > Docs at https://docs.microsoft.com/en-us/azure/azure-resource-manager/resource-manager-common-deployment-errors#noregisteredproviderfound has the command az provider show -n Microsoft.Web --query "resourceTypes[?resourceType=='sites'].locations" which returns an empty list for Microsoft.Sql. So this doc page also needs to be clarified somehow.

Using az provider show -n Microsoft.SQL --query "resourceTypes[?resourceType=='servers/databases'].locations should work, the document uses appservice as the example, so you have to tweak across

Also if I have already registered then the help text is misleading. It should just succeed or maybe write text like “already registered”.

This was fixed last month 😃