[jdk8u-dev] RFR: 8323197: [8u] building doc fixes

[Zdenek Zambersky]

Fixes for various issues in "building" doc:
- removed information about mercurial and replaced with git as appropriate (as mercurial repos are no longer active)
- fixed broken section references
- fixed broken links, updated to web archive, where original site no longer exists ( with exception of `Windows FreeType DLL build instructions` link, where archived page is not available :( )
- updated md tables to use `|`, so they would correctly display in GH (e.g. compare [old](https://github.com/openjdk/jdk8u-dev/blob/d898d4018e0a16f2115f4b1cbf93eb5e653b789b/doc/building.md#cygwin) [new](https://github.com/zzambers/jdk8u-dev/blob/fix-doc/doc/building.md#cygwin))
- avoided use of block quotes (using `>`) in md, as it produces ugly result in GH (e.g. compare [old](https://github.com/openjdk/jdk8u-dev/blob/d898d4018e0a16f2115f4b1cbf93eb5e653b789b/doc/building.md#configure-options) [new](https://github.com/zzambers/jdk8u-dev/blob/fix-doc/doc/building.md#configure-options))
- regenerated html (visual changes in generated html are quite minor)

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Commit messages:
 - building doc fixes

Changes: https://git.openjdk.org/jdk8u-dev/pull/416/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk8u-dev&pr=416&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8323197
  Stats: 465 lines in 2 files changed: 36 ins; 108 del; 321 mod
  Patch: https://git.openjdk.org/jdk8u-dev/pull/416.diff
  Fetch: git fetch https://git.openjdk.org/jdk8u-dev.git pull/416/head:pull/416

PR: https://git.openjdk.org/jdk8u-dev/pull/416