chore: set context timeout for access to kv

[aramase]

What this PR does / why we need it:

• Sets context timeout to 1m50s for access to kv. This ensures the request is terminated and error is returned when time to access kv takes > 2m. The default volume timeout for kubelet is 2m3s and this change honors the value. If the context in provider is not set, then the driver will terminate the process based on the context, but the error from provider will not be surfaced to the user.

Sample error when network policies deny outbound traffic in cluster -

time="2020-07-09T19:07:35Z" level=info msg="time=\"2020-07-09T18:57:35Z\" level=info msg=\"using pod identity to access keyvault\"\ntime=\"2020-07-09T18:57:35Z\" level=info msg=\"mounting secrets store object content for kube-system/nginx-secrets-store-env-var\"\ntime=\"2020-07-09T18:57:35Z\" level=info msg=\"objects: array:\\n  - |\\n    objectName: kv\\n    objectType: secret           # object types: secret, key or cert\\n    objectVersion: \\\"\\\"            # [OPTIONAL] object versions, default to latest if empty\\n\"\ntime=\"2020-07-09T18:57:35Z\" level=info msg=\"unmarshaled keyVaultObjects: [{kv   secret}]\"\ntime=\"2020-07-09T18:57:35Z\" level=info msg=\"keyVaultObjects len: 1\"\ntime=\"2020-07-09T18:57:35Z\" level=info msg=\"azure: using pod identity to retrieve token\"\ntime=\"2020-07-09T18:58:05Z\" level=info msg=\"accesstoken: eyJ0##### REDACTED #####l20w\"\ntime=\"2020-07-09T18:58:05Z\" level=info msg=\"clientid: ee32##### REDACTED #####0e49\"\n"
time="2020-07-09T19:07:35Z" level=error msg="error invoking provider, err: exit status 1, output: time=\"2020-07-09T19:07:35Z\" level=fatal msg=\"[error] : failed to get objectType:secret, objectName:kv, objectVersion:: keyvault.BaseClient#GetSecret: Failure sending request: StatusCode=0 -- Original Error: Get https://kv.vault.azure.net/secrets/kv/?api-version=2016-10-01: dial tcp: i/o timeout\"\n for pod: c1f448b7-b752-431e-ad33-521c2abb8204, ns: kube-system"
time="2020-07-09T19:07:35Z" level=error msg="GRPC error: error mounting secret time=\"2020-07-09T19:07:35Z\" level=fatal msg=\"[error] : failed to get objectType:secret, objectName:kv, objectVersion:: keyvault.BaseClient#GetSecret: Failure sending request: StatusCode=0 -- Original Error: Get https://kv.vault.azure.net/secrets/kv/?api-version=2016-10-01: dial tcp: i/o timeout\"\n for pod: c1f448b7-b752-431e-ad33-521c2abb8204, ns: kube-system"

The request only times out after 10m as there is no context defined

Which issue(s) this PR fixes (optional, using fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when the PR gets merged):
Fixes #

Special notes for your reviewer:

[aramase]

/azp run pr-e2e-azure

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[ritazh]

Should we make this configurable and default to 1m50s?

[aramase]

@ritazh Good idea! We can add a context-timeout flag in the provider and default that to 1m50s for the time being. For addition of this flag as mandatory in the driver, I'll add an item in the agenda next week so we can discuss how we want to do this? This would require an update in all the providers to support the flag before we add to driver.

[ritazh]

lgtm