Add support for root level lists under namespace

[niveathika]

Purpose

Add support for root level lists under namespace as follows,

testTransports:
  - testTransport:
      name: abc
      port: 9090
      secure: true
      desc: This transport will use 8000 as its port
      password: ${sec:conn.auth.password}
  - testTransport:
      name: pqrs
      port: ${env:pqr.http.port}
      secure: ${sys:pqr.secure}
      desc: This transport will use ${env:pqr.http.port} as its port. Secure - ${sys:pqr.secure}
  - testTransport:
      name: xyz
      port: ${env:xyz.http.port,9000}
      secure: ${sys:xyz.secure,true}
      desc: This transport will use ${env:xyz.http.port,8888} as its port

Goals

Add support for root level lists under namespace which can be retrived through configProvider.getConfigurationObject("") and processed as needed
As per discussions under https://groups.google.com/forum/?hl=en#!topic/siddhi-dev/j3W4mA8jjQ8

Approach

When dumping we if the TAG is not Map, them we dump it as a sequence and return.

User stories

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Release note

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Documentation

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Training

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Certification

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Marketing

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Automation tests

• Unit tests - Attached to the PR
• Integration tests - N/A

Security checks

• Followed secure coding standards in http://wso2.com/technical-reports/wso2-secure-engineering-guidelines? yes
• Ran FindSecurityBugs plugin and verified report? yes
• Confirmed that this PR doesn't commit any keys, passwords, tokens, usernames, or other secrets? yes

Samples

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Related PRs

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Migrations (if applicable)

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Test environment

JDK 1.8.0_191

Learning

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