Add a Contributor's Guide feature to the docs (#228)

* create contributor's guide

* add guidelines for making good PR

* good pull request edits

* 1st Draft of COntributor's Guide

* minor formatting edits

* Add instructions for srw_common module load

* fix module files guidance

* fix typo

* update Intro & BuildRunSRW based on Mark's feedback

* minor intro updates

* add info on documentation requirements

* 1st round of J. Beck's edits

* add textonly issue template + minor typo-type fixes

* minor edits/formatting

* remove pylintrc requirement

* fixed .yaml & other minor

Co-authored-by: gspetro <gillian.s.petro@gmail.com>

.github/ISSUE_TEMPLATE/textonly_request.md

@@ -0,0 +1,20 @@
+---
+name: Text-only request
+about: Suggest an idea for this project
+title: ''
+labels: textonly
+assignees: ''
+
+---
+
+## Description
+Provide a clear and concise description of the problem to be solved.
+
+## Solution
+Add a clear and concise description of the proposed solution.
+
+## Alternatives (optional)
+If applicable, add a description of any alternative solutions or features you've considered.
+
+## Related to (optional)
+Directly reference any issues or PRs in this or other repositories that this is related to, and describe how they are related.