Add TigerMail email sending template

[NatanelBarazani]

Description

<-- short description of the template(s) and/or reason for update -->

Type of change

Please mark options that are relevant.

• New template
• Bug fix (non-breaking change which fixes an issue in the template)
• New feature (non-breaking change which adds functionality to the template)
• Breaking change (fix or feature that would cause existing template behavior to be not backward compatible)

How Has This Been Tested?

Please mark the following checks done

• Schema validated using JSON Schema template.schema
• Template functionality checked using Online Editor
• Template is checked using template linter
• Template file name follows the pattern <providerId>.<serviceId>.json
• resource URL provided with logoUrl is actually served by a webserver

Example variable values

<-- to make review process easier please provide example set of variable values for this template -->

<-- Example: -->

var1: aaa
var2: foo.com

<-- Or provide the whole testData object from the Online Editor after testing and using "Add as test" button -->

"testData": {
    "testset": {
      "variables": {
        "domain": "example.com",
        "host": "foo",
        "example": "bar"
      },
      "results": [
        {
          "type": "TXT",
          "name": "foo",
          "ttl": 86400,
          "data": "\"bar\""
        }
      ]
    }
  }

[github-actions]

Linter OK:

Linter result for tigermail.io.email-send.json
{"level":"warn","template":"tigermail.io.email-send.json","error":"unexpected http status 404","logoUrl":"https://tigermail.io/logo.svg","code":"DCTL1010","dctl_note":"logo check failed","time":1766948371}