Create custom ADR GitHub template(s) (#290)

This changeset adds a custom issue template and form for use within GitHub itself to help draft new Architectural Decision Records (ADRs).

Note that we'll still ultimately have to create the actual ADR as a Markdown file that lives in the `doc/adrs/` folder.

Signed-off-by: Carlo Costino <carlo.costino@gsa.gov>

.github/ISSUE_TEMPLATE/create-new-adr-form.yml

@@ -0,0 +1,120 @@
+name: Create a new ADR
+description: Create a new Architectural Decision Record.
+title: "[ADR]: "
+labels: ["documentation"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Use this form to create a new Architectural Decision Record.
+  - type: input
+    id: title
+    attributes:
+      label: ADR Title
+      description: What is the title of this ADR?
+      placeholder: e.g., Establishing ADRs for US Notify
+    validations:
+      required: true
+  - type: input
+    id: created_date
+    attributes:
+      label: Created Date
+      description: What is the date this ADR is being created?
+      placeholder: MM/DD/YYYY
+    validations:
+      required: true
+  - type: dropdown
+    id: status
+    attributes:
+      label: Status
+      description: What is the current status of this ADR?
+      options:
+        - Proposed
+        - Accepted
+        - Rejected
+        - Deprecated
+        - Superseded By
+    validations:
+      required: true
+  - type: input
+    id: superseded_by
+    attributes:
+      label: Superseded By
+      description: If this ADR is superseded by another, which one is it?
+      placeholder: e.g., ADR-0001
+    validations:
+      required: false
+  - type: input
+    id: author
+    attributes:
+      label: Author
+      description: Who is the author(s) of this ADR?
+      placeholder: Enter your GitHub username here, and anyone else helping author this
+    validations:
+      required: true
+  - type: input
+    id: stakeholders
+    attributes:
+      label: Stakeholders
+      description: Who are the stakeholders of this ADR?
+      placeholder: Enter their GitHub username(s) here
+    validations:
+      required: false
+  - type: input
+    id: linked-github-issue
+    attributes:
+      label: Related Issue(s)
+      description: List any related GitHub issues to this ADR here (issue number only).
+      placeholder: e.g., 288
+    validations:
+      required: false
+  - type: textarea
+    id: context-and-problem-statement
+    attributes:
+      label: Context and Problem Statement
+      description: Explain the nature of the problem, challenge, or decision to be made here.
+      placeholder: Be as succinct as possible, but do not leave out any details.  State things matter of factly and as objectively as you can.
+    validations:
+      required: true
+  - type: textarea
+    id: decision-drivers
+    attributes:
+      label: Decision Drivers
+      description: List anything that plays a major role in making a decision here.
+    validations:
+      required: true
+  - type: textarea
+    id: security-compliance-considerations
+    attributes:
+      label: Security Compliance Considerations
+      description: List any security concerns in this section along with any relevant details.
+    validations:
+      required: true
+  - type: textarea
+    id: considered-options
+    attributes:
+      label: Considered Options
+      description: List all options that have either been discussed or thought of as a potential solution to the context and problem statement.  Include any pros and cons with each option.
+    validations:
+      required: true
+  - type: input
+    id: proposed-option
+    attributes:
+      label: Proposed Option
+      description: If an option is already clear or has been chosen, please name it here.
+    validations:
+      required: false
+  - type: textarea
+    id: proposed-option-justification
+    attributes:
+      label: Proposed or Chosen Option
+      description: Summarize the decision for the proposed/chosen option here, including a list of positive and negative consequences.
+    validations:
+      required: false
+  - type: textarea
+    id: validation-and-next-steps
+    attributes:
+      label: Validation and Next Steps
+      description: If an option has already been chosen and justified, summarize or list the validation and next steps that came from the decision.
+    validations:
+      required: false