Expose an API for applying the SslContext's default configuration prior any other configuration

[violetagg]

SslProvider.SslContextSpec#sslContext(SslProvider.ProtocolSslContextSpec)
provides, specific for the protocol, default configuration (DefaultSslContextSpec,
TcpSslContextSpec, Http11SslContextSpec, Http2SslContextSpec).
As opposed to SslProvider.SslContextSpec#sslContext(SslContextBuilder),
the default configuration is applied before any other custom configuration.

Fixes #1543

[codecov-io]

Codecov Report

Merging #1573 (555d330) into master (5ec067d) will decrease coverage by 0.06%.
The diff coverage is 76.11%.

@@             Coverage Diff              @@
##             master    #1573      +/-   ##
============================================
- Coverage     71.00%   70.94%   -0.07%     
- Complexity     1894     1998     +104     
============================================
  Files           146      153       +7     
  Lines          9294     9749     +455     
  Branches       1271     1328      +57     
============================================
+ Hits           6599     6916     +317     
- Misses         2037     2140     +103     
- Partials        658      693      +35     

Impacted Files	Coverage Δ	Complexity Δ
...ore/src/main/java/reactor/netty/NettyPipeline.java	100.00% <ø> (ø)	1.00 <0.00> (ø)
...va/reactor/netty/resources/ConnectionProvider.java	56.41% <ø> (ø)	6.00 <0.00> (ø)
.../java/reactor/netty/tcp/DefaultSslContextSpec.java	0.00% <0.00%> (ø)	0.00 <0.00> (?)
...ore/src/main/java/reactor/netty/tcp/TcpServer.java	62.74% <ø> (ø)	16.00 <0.00> (ø)
...r/netty/http/brave/TracingHttpClientDecorator.java	82.85% <ø> (ø)	2.00 <0.00> (ø)
...tp/src/main/java/reactor/netty/http/HttpInfos.java	88.88% <ø> (ø)	4.00 <0.00> (ø)
...tor/netty/http/client/FailedHttpClientRequest.java	35.48% <0.00%> (-1.19%)	5.00 <0.00> (ø)
...p/server/logging/AbstractAccessLogArgProvider.java	100.00% <ø> (ø)	18.00 <0.00> (-2.00)
...e/src/main/java/reactor/netty/tcp/SniProvider.java	84.61% <33.33%> (-7.06%)	4.00 <0.00> (ø)
...main/java/reactor/netty/tcp/TcpSslContextSpec.java	47.36% <47.36%> (ø)	7.00 <7.00> (?)
... and 59 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 22a49de...555d330. Read the comment docs.

[rstoyanchev]

Looks good, some minor comments below.