*/kf5-*: (KDE Frameworks) lighten dependencies

• ECM (extra-cmake-modules) is only ever a build-dep and was missing in some places where it was previously pulled in implicitly
• Qt testlib is only a build-dep

While here

• conventionally, the _build and _run items in USE_KDE and USE_QT are sorted to the end, and they start a new line in the Makefile
• remove tcberner's created-line (confirmed on IRC)
• use DISTVERSION everywhere
• reduce inter-framework dependencies using the tooling proposed by tcberner in https://reviews.freebsd.org/D27304

Some PORTREVISION may have jumped by more than 1, since this commit
is a squash of a long string of updates where I may have bumped a
port once for ecm_build, and a second time for other lightening-up.