Convert cwes list to markdown with fewer rows and columns

[sei-renae]

Resolves #529
Resolves #530
Resolves #713

The CWEs list on reference/decision_points/exploitation/#cwe-ids-for-poc has many rows wherein the 'Possible POC' = 'no'; therefore, these rows are irrelevant to Exploitation. In rows where 'Possible POC' = 'no', 'In NVD's CWE slice' is also always 'no' and information about the exploit is nan.
Furthermore, #529 describes a hypothetical list of CWEs, but was not updated after this list was obtained.

This PR cleans the CWEs list to that:

• only rows with column 'Possible POC' = 'yes' are included, thus eliminating rows where column element is nan to resolve Empty csv columns print nan on github pages #713.
• column 'In NVD's CWE slice' is removed because the answer is always 'yes'.
• column CWE-ID is prefixed with 'CWE-' and hyperlinked to the corresponding CWE.
• columns Tools and Links are merged as hyperlinks to the tools.
• the need for side-scrolling is eliminated to resolve Eliminate need for side scrolling of CWE table in exploitation.md #530.
• instead of a csv, this is a markdown file.

The new table will look like this:

The PR also updates the language described in SSVC/docs/topics/information_sources.md to resolve #529 .