Update outdated links

[vkrasnovyd]

Resolves #148

Also updated outdated link to the BSD-3-Clause license:

• old: https://www.oasis-open.org/sites/www.oasis-open.org/files/BSD-3-Clause.txt
• new: https://opensource.org/license/BSD-3-Clause (source: https://www.oasis-open.org/licenses/)

[bernhardreiter]

Inspected the changes and made a few small improvements.

Dear maintainers (@sthagen, @justmurphy, @tschmidtb51), please merge. This improvement makes sure that potential future contributors will see the current information on how to contribute (see #148 for the problem it solves).

[tschmidtb51]

Overall, it looks like the transformations from HMTL to Markdown with a small bunch of fixes as we changed the default branch...

I found one issue in the CVRF README.

@OASIS-OP-Admin: Can we do that change as suggested?

[sthagen]

As @tschmidtb51 stated, we need to know, if someone else than OASIS should change and I myself am not sure what the goal of the changes is (aside from the license URL fix). Thanks.

[sthagen]

Cf. my comment from a minute ago or so. Thanks.

[bernhardreiter]

we need to know, if someone else than OASIS should change

The changes as we have intended them were meant to keep the contents itself.
Only the representation within this repository should have been improved the fixed contents where it was broken. (So from my point of view official clearance is not necessary, unless the representation needs to be cleared as well. )

I myself am not sure what the goal of the changes is (aside from the license URL fix).

#148 described the main problem: broken internal links towards the wrong branch.

Additional fixes and improvements:

• simply representation of links from HTML (which is allowed in Markdown) to a relative Markdown link. It is easier to read and point to the current branch which is good for developing changes in other git branches.
• Fix for bad contents in

  csaf-documentation/examples/cvrf/README.md

  Line 573 in 26a7469

  =======

• (fix license link to a working)

[claurau]

LGTM