Description: Action: Add new Subscriber creates subscriber with 'Email type: html' only, no matter what value was input into 'Email type' field

STR:

1. Create flow: simple trigger -> mailchimp: Add new Subscriber, input:
   
2. Retrieve sample:

AR: FInd in sample: "email_type": "html"
ER:

1. "email_type": "text"
   OR
2. in case if "email_type": "text" cannot be set due to mailchimp API behaviour - enum list of available values for email_type should be fixed:
   

Description: API Key is sensitive data, so API Key field type should be changed to PasswordFieldView, in order to not show actual data on UI

Description: in this PR will be added stub into code in order to avoid valid credentials verification failure, as it makes imposible to create new creds and use component.

However, we need to implement proper credentials verification mechanism

STR:

1. Go to Credentials page
2. Start creating new creds: input valid data
3. Click on Verify button

AR: Creds are not verified, however on UI it looks like they ware verified

logs:

Starting your Docker container ...
[INFO  tini (1)] Spawned child process '/run.sh' with pid '7'
Starting application in apprunner...
Will try to start app at /home/apprunner
node: /usr/lib/libstdc++.so.6: no version information available (required by node)
node: /usr/lib/libstdc++.so.6: no version information available (required by node)
node: /usr/lib/libstdc++.so.6: no version information available (required by node)
node: /usr/lib/libstdc++.so.6: no version information available (required by node)
node: /usr/lib/libstdc++.so.6: no version information available (required by node)
node: /usr/lib/libstdc++.so.6: no version information available (required by node)
node: /usr/lib/libstdc++.so.6: no version information available (required by node)
node: /usr/lib/libstdc++.so.6: no version information available (required by node)
[INFO  tini (1)] Main child exited normally (with status '0')

ER: Creds are actually verified, information regarding successfully verified creds are present in logs and on UI

Description: It is not obvious that email was unsubscribed when output is - {}

STR:

1. create flow: step1 - simple trigger
2. Add step2: mailchimp-component:Add new Subscriber - add new test Subscriber
3. add step3: mailchimp-component:Unsubscribe - use email of created Subscriber from step2
4. See output after sample retrieved on step3: {}

AR: Output {}
ER: Need to research API docs to find out what we can provide user with in order to understand that action was run with success.

STR:

1. Create new subscription.

2. Try to update created subscription:
   

3. See that some properties are not updated
   

AR: Some properties are not updated in Add new Subscriber action and no error message shown

ER:
depends on API:

• if possible - throw an error message when a property is not updated
• if API does not provide with this option - specify this behavior in README, because as a user I expect a property to be updated according to specified value if no error thrown

Description: Add output metadata to all Retrieve Customer action and update in Upsert Customer and Upsert Subscription actions, so Generate Stub Sample button will appear:

For component

• Update according to existing README template
• add API docs link: https://mailchimp.com/developer/reference/

For each action:
1.
Rename Unsubscribe Action -> Archive a list member
Add action description: Use this action in order to archive a list member.
Add to readme that it use method : DELETE /lists/{list_id}/members/{subscriber_hash} Archive a list member`

Rename Add new Subscriber Action -> Upsert a list member
Add action description: Use this action in order to add or update a list member
Add to readme that it use method : PUT | /lists/{list_id}/members/{subscriber_hash} | Add or update a list member`

Rename Upsert customer action -> Upsert a customer
Add action description: Use this action in order to add or update a customer
Add to readme that it use method: PUT | /ecommerce/stores/{store_id}/customers/{customer_id} | Add or update a customer`