feat: create a character counter on the input field

[taraculpin]

Description

Adds an optional character counter to the input field with a configurable element determining after how many entered characters it appears.

Requirements

• maxlength and characterCounterTrigger attributes need to be set on the input for the character counter to appear.
  • If the maxlength and characterCounterTrigger attributes are the same, then the character counter will display before any value has been entered
  • If the characterCounterTrigger is 5 for example, the character counter will display when there are only 5 characters remaining. If the maxlength were set to 20, the character counter would display after 15 characters had been entered.

Design link: (link to design or delete if not required) - TBC
Screenshot:

Checklist:

• The commit messages follow the convention for this project
• I have provided an adequate amount of test coverage
• I have added the functionality to the test app
• I have provided a story in storybook to document the changes
• I have added the documentation
• I have added any new public feature modules to public-api.ts