[Tests] remove bigArrays which were not fully release from watch list (and still fail the test)

This is to prevent future tests from failing due to these arrays
[TEST] Stabelize BWC tests for version < 1.1.0
Docs: Add clarifying text about regexp and terms

For the casual reader, the reference to "term queries" may be glossed over, yielding an unexpected result when using `regexp` queries.
This attempts to make that distinction more prominent.

Closes #6698
[TEST] Expose `tests.filter` for elasticsearch tests.

`-Dtests.filter` allows to pass filter expressions to the elasticsearch
tests. This allows to filter test annotaged with TestGroup annotations
like @Slow, @Nightly, @Backwards, @Integration with a boolean expresssion like:

 * to run only backwards tests run:
     `mvn -Dtests.bwc.version=X.Y.Z -Dtests.filter="@backwards"`
 * to run all integration tests but skip slow tests run:
     `mvn -Dtests.filter="@integration and not @slow"
 * to take defaults into account ie run all test as well as backwards:
     `mvn -Dtests.filter="default and @backwards"

This feature is a more powerful alternative to flags like
`-Dtests.nighly=true|false` etc.

Closes #6703
Analysis: Add additional Analyzers, Tokenizers, and TokenFilters from Lucene

Add `irish` analyzer
Add `sorani` analyzer (Kurdish)

Add `classic` tokenizer: specific to english text and tries to recognize hostnames, companies, acronyms, etc.
Add `thai` tokenizer: segments thai text into words.

Add `classic` tokenfilter: cleans up acronyms and possessives from classic tokenizer
Add `apostrophe` tokenfilter: removes text after apostrophe and the apostrophe itself
Add `german_normalization` tokenfilter: umlaut/sharp S normalization
Add `hindi_normalization` tokenfilter: accounts for hindi spelling differences
Add `indic_normalization` tokenfilter: accounts for different unicode representations in Indian languages
Add `sorani_normalization` tokenfilter: normalizes kurdish text
Add `scandinavian_normalization` tokenfilter: normalizes Norwegian, Danish, Swedish text
Add `scandinavian_folding` tokenfilter: much more aggressive form of `scandinavian_normalization`
Add additional languages to stemmer tokenfilter: `galician`, `minimal_galician`, `irish`, `sorani`, `light_nynorsk`, `minimal_nynorsk`

Add support access to default Thai stopword set "_thai_"

Fix some bugs and broken links in documentation.

Closes #5935
[TEST] Wait for cluster consistency before tests starts
Fix doc formatting. Norwegian stemmers and Scandinavian normalizers
were missing commas between entries.
[TEST] Exclude SORANI analyzer if compatibility version is < 1.3.0
Docs: Fix typo in timestamp-field.asciidoc

Closes #6661
Docs: unescape regexes in Pattern Tokenizer docs

Currently regexes in Pattern Tokenizer docs are escaped (it seems according to Java rules). I think it is better not to escape them because JSON escaping should be automatic in client libraries, and string escaping depends on a client language used. The default pattern is `\W+`, not `\\W+`.

Closes #6615
[Discovery] Fault detection should also check  cause exceptions for disconnects

The change introduced in #6686 checks for ConnectionTransportException during pinging. However, transport layer wraps it in  SendRequestTransportException
[TEST] Split up random bulks more often and also if the document set is smallish
[TEST] disable BWC tests for version < 1.1.0
[TEST] only call TestCluster#afterTest() if cluster was successfully initialized
[Discovery] immediately start Master|Node fault detection pinging

After a node joins the clusters, it starts pinging the master to verify it's health. Before, the cluster join request was processed async and we had to give some time to complete. With  #6480 we changed this to wait for the join process to complete on the master. We can therefore start pinging immediately for fast detection of failures. Similar change can be made to the Node fault detection from the master side.

Closes #6706
[TEST] Include mapping in failure
Docs: fixed ICU plugin documentation

add ICU Normalization CharFilter to docs

Closes #6711
[DOCS] Add information regarding _type parameter requirement for _mget

Closes #6670.
[DOCS] Add information regarding _type parameter requirement for _mget

Change ID to `[[mget-type]]`

Closes #6670.
Fix github download link when using specific version