Remove zendesk and asana connectors

[NipunaRanasinghe]

Description

$subject, as Zendesk and Asana connectors are moved out and will be maintained under dedicated repositories (along with the new connector reviving effort)

Related to ballerina-platform/ballerina-library#6185 and ballerina-platform/ballerina-library#6238

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• Test A
• Test B

Test Configuration:

• Ballerina Version:
• Operating System:
• Java SDK:

Checklist:

Changes to OpenAPI definition

• Modified info section of the OpenAPI definition file - Example

  • description - what the connector is about
  • x-ballerina-init-description OpenAPI extension - connector initialization details
  • x-ballerina-display OpenAPI extension - connector name and path to the connector icon

• Added proper description each API Key, if API Key authentication is defined in OpenAPI definition file

Changes to connector module

• Added license header at the top of each .bal file.
• Added Package.md as per the guide here
• Added Module.md for the module of the connector as per the guide here
• Added connector icon to the root of the connector. Icon needs to be a png of 200x200 px size with name icon.png
• Added Ballerina.toml file with following information. For keywords refer to guide

Verifying connector module

• Compiled the connector successfully with the targeted ballerina version.
• Conducted smoke tests on the connector (Recommended when OpenAPI definition is obtain from an unofficial source)

Security checks

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

[ThisaruGuruge]

LGTM