Replace datatracker's use of bleach

[rjsparks]

Description

Bleach is long deprecated. Replace it with something being maintained. nh3 is a good candidate.

Code of Conduct

• I agree to follow the IETF's Code of Conduct

[nouralmaa]

are you also looking for an alternative to the bleach linker? (afaik nh3 doesn't have built in reg exs)

[jennifer-richards]

are you also looking for an alternative to the bleach linker? (afaik nh3 doesn't have built in reg exs)

Yes, we'll want to keep supporting the things we do with the linker.