fix: markdown renderer use ExecutableName instead atlantis

[krrrr38]

what

• make MarkdownRenderer private
  • no need public fields for more immutable
• ExecutableName is available on markdown renderer common data
  • pass ExecutableName into markdown renderer
• replace template atlantis name with .ExecutableName

why

When using --executable-name=atlantis-dev, some messages still contain atlantis.

tests

• existed tests keep success
• check all atlantis words are replaced like followings

before

✘╹◡╹✘☆  ag "\`atlantis" server/events/templates/
server/events/templates/multi_project_plan.tmpl
8:    * `atlantis apply`
10:    * `atlantis unlock`{{end}}{{end}}{{ template "log" . }}

server/events/templates/unwrapped_err.tmpl
7:    * `atlantis approve_policies`

server/events/templates/single_project_plan_success.tmpl
8:    * `atlantis apply`
10:    * `atlantis unlock`{{ end }}{{ template "log" . }}

after

✘╹◡╹✘☆  ag "atlantis" server/events/templates/ | wc -l
       0

references

n/a

[nitrocode]

can we keep this all lowercase for now?

[krrrr38]

@nitrocode reverted these changes. now ready for review 🙇

tests failing

[nitrocode]

@krrrr38 I had one comment and I noticed that tests are failing.

[nitrocode]

Thank you @krrrr38 !