Merge r1804096, r1807238, r1809981, r1810088, r1810089 from trunk:

bumping version, removing some unused code, fixes in base64url from mod_md

On the trunk:

  *) mod_http2: DoS flow control protection is less agressive as long as active tasks stay
     below worker capacity. Intended to fix problems with media streaming. 


On the trunk:
mod_http2: v0.10.12, removed optimization for mutex handling in bucket beams that could lead to assertion failure in edge cases.


reverting r1807238 bc not addressing the issue https://github.com/icing/mod_h2/issues/120

mod_http2: non-dev 1.10.12 for backport


Submitted by: icing
Reviewed by: icing, steffenal, ylavic


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1812081 13f79535-47bb-0310-9956-ffa450edef68