chore: add issue template for proposing new dev-tools (#19001)

A while back @csantanapr proposed to add devcontainers to the Argo CD
tree (see #17286). After a few rounds in the contributors' meeting it
was proposed to add an issue template, so that for tools like this
there would at least be two maintainers that commit to keeping it
up-to-date.

See [proposal](https://docs.google.com/document/d/1mvfnaeCQgVpCixHchjMPtoW5WdtzLAp8cIr3nWFUSiU/edit)
for context.

Signed-off-by: Blake Pettersson <blake.pettersson@gmail.com>

.github/ISSUE_TEMPLATE/new_dev_tool.md

@@ -0,0 +1,43 @@
+---
+name: New Dev Tool Request
+about: This is a request for adding a new tool for setting up a dev environment.
+title: ''
+labels: ''
+assignees: ''
+---
+
+Checklist:
+
+* [ ] I am willing to maintain this tool, or have another Argo CD maintainer who is. 
+* [ ] I have another Argo CD maintainer who is willing to help maintain this tool (there needs to be at least two maintainers willing to maintain this tool)
+* [ ] I have a lead sponsor who is a core Argo CD maintainer
+* [ ] There is a PR which adds said tool - this is so that the maintainers can assess the impact of having this in the tree
+* [ ] I have given a motivation why this should be added
+
+### The proposer
+
+<-- The username(s) of the person(s) proposing the tool -->
+
+### The proposed tool
+
+<!-- The tool itself, with a link to the tool’s website -->
+
+### Motivation
+
+<!-- Why this tool would be useful to have in the tree. --> 
+
+### Link to PR (Optional)
+
+<!-- A PR adding the tool to the tree -->
+
+### Lead Sponsor(s)
+
+Final approval requires sponsorship from at least one core maintainer.
+
+- @<sponsor-1>
+
+### Co-sponsors
+
+These will be the co-maintainers of the specified tool.
+
+- @<sponsor-1>