DTS documentation improvements

[pietrushnic]

Dasharo version

DTS v1.1.1

Affected component(s) or functionality

• Documentation

Brief summary

I don't think it make sense to create issue per every minor problem I see, because of that I decided to create one issue and if it would be needed we can create dedicated tickets.

• readme has no word about the fact build is cached and that artifacts will be downloaded from our mirror, but there is suggestion that build will take time
• there are simple formatting mistakes in readme: https://github.com/Dasharo/meta-dts#build-image-with-uefi-secure-boot-support
• shouldn't we link to releases?
• We have to clearly distinguish what belongs to meta-dts readme and what belongs to dasharo docs DTS section otherwise it would be hard to keep track of changes in both places, now we tracking supported platforms in both places, meta-dts readme has no information about version in which MSI PRO Z690-A DDR4 is supported
• documentation request: how to perform DTS release? I would like to know how to perform such release from start to end, knowing that procedure would be easier to offload it and check for potential issues during the process.

[TomaszAIR]

Connected issue #337, both should be handled before next release