Create page list of codecheckers

[angelina-momin]

Solves issue #71 Related codecheck repo PR #90

The render_register function now creates a list of codecheckers as shown in the image below. The codechecker name links to the codecheck website with all their codechecks. The orcid ID links to their orcid pages. The "JSON" links to the index.json file

Changes made:

• Bumped version to 0.4.0
• Move all config settings from register.R to a new inst/extdata/config.R file.
• Created functions render_table_codecheckers for html and json files which are now called in render_register function
• Added new template file for non register tables like the codecheckers table
• Move all templates to inst/extdata/templates folder in this repo
• Update the Rmarkdown files for the new functions

[angelina-momin]

Having conflicts that I am struggling to resolve. Decided to create a new branch to keep things simpler and close this PR. New PR: #52