Update existing plugins with docs

[Andrew-Morozko]

Updated	Tests fixed	plugin	type	name
[x]	[x]	builtin	content provider	blockquote
[x]	[x]	builtin	content provider	code
[x]	[x]	builtin	content provider	frontmatter
[x]	[x]	builtin	content provider	image
[x]	[x]	builtin	content provider	list
[x]	[x]	builtin	content provider	table
[x]	[x]	builtin	content provider	text
[x]	[x]	builtin	content provider	title
[x]	[x]	builtin	content provider	toc
[x]	[x]	builtin	data source	csv
[x]	[x]	builtin	data source	inline
[x]	[x]	builtin	data source	json
[x]	[x]	builtin	data source	rss
[x]	[x]	builtin	data source	txt
These	changes	got	reverted	temporarily
[ ]	[ ]	elastic	data source	elastic_security_cases
[ ]	[ ]	elastic	data source	elasticsearch
[ ]	[ ]	github	data source	github_issues
[x]	[ ]	graphql	data source	graphql
[ ]	[ ]	hackerone	data source	hackerone_reports
[ ]	[ ]	nist_nvd	data source	nist_nvd_cves
[x]	[ ]	openai	content provider	openai_text
[x]	[ ]	opencti	data source	opencti
[x]	[ ]	postgresql	data source	postgresql
[ ]	[ ]	splunk	data source	splunk_search
[x]	[ ]	sqlite	data source	sqlite
[ ]	[ ]	stixview	content provider	stixview
[x]	[ ]	terraform	data source	terraform_state_local
[ ]	[ ]	virustotal	data source	virustotal_api_usage

Besides docs update the PR does refactoring of the diagnostic asserts, factoring out common cty->data conversion code, and other small tweaks

[Andrew-Morozko]

PR not fully ready, un-drafting to run the tests

[Andrew-Morozko]

I decided to revert some documentation changes to merge this PR faster, fixing tests is tedious and could be done later.

New docs are available for all of the builtin plugins, ready to merge!