Fix illustration for T3 context in "Important terms and concepts"

[alxlo]

• Fonts don't render well
• Avoid abbreviation T3T
• Consistent terms in regard to text

[alxlo]

[mahduse]

for all drawings:

• fonts substituted ubuntu, cubano -> arial (Narrow & Black)
• labeling in white color

for context diagram -shorthand's removed -labeling of the pictograms removed

[mahduse]

[mahduse]

[alxlo]

Sorry, but I#ve to reopen this. There are rendering issues with our tool chain. Probably some font problem.

[alxlo]

todo for @alxlo : experiment with fonts, tell @ralf which fonts work

[alxlo]

@DE-ZM commented:

Something in the pipeline is missing. T3Participant cannot directly deliver CPSA-training. Instead, an interview for the accreditation is required. This step can also be illustrated in this picture for a better understanding.

I think this is an important point and should be included in this image. @mahduse - could you fix this?

[mahduse]

I have corrected all images. SVG images are not rendered correctly in adoc. That's why I exported the images in png format. The SVG version will also be included. Furthermore the font has been changed to Roboto. This is the official font for curricula. Content adjustments (labelling, abbreviations) have been adapted accordingly.