<Swing Dev> RFR: 8260314: Replace border="1" on tables with CSS

[Alexey Ivanov]

Replace presentational attribute `border="1"` on `<table>` element with CSS styles:
table {border: outset 1px}
th, td {border: inset 1px} 

These declarations produce the same rendering as the default one in Firefox and Edge. 

Another option is to use `solid` in both cases.

-------------

Commit messages:
 - Move table styles to common <style> block
 - 8260314: Replace border="1" on tables with CSS

Changes: https://git.openjdk.java.net/jdk/pull/2210/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2210&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8260314
  Stats: 61 lines in 6 files changed: 25 ins; 0 del; 36 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2210.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2210/head:pull/2210

PR: https://git.openjdk.java.net/jdk/pull/2210