Cleanup EideticRequestMonitor
Add a timeout on the failedLatch which waits for the master to disappear

- removed the electedLatch since we can use cluster.await instead
Fixed cardinality calculations for bidirectional patterns
Added handling of optional match to QueryGraphCardinalityModel
Fixes a license header
Merge branch '2.1-maint'
Evict from cache as late as possible in race test.
Exact number of relationships given node label.

The CountsStore maintains the exact number of relationships in the
database that either starts or ends in a node with a given label. Counts
are maintained both in total, and by relationship type, but only for one
label, i.e. number of relationships that starts in a node with a given
label and ends in a node with a given label is not maintained.
Fix an issue reading transaction logs over network.

NetworkReadableLogChannel should not check if there is enough data available before reading.
Netty will throw an IndexOutOfBoundsException if the network stream doesn't supply enough data
to match the requested type.

ReadPastEndException was refactored as a singleton without stack trace as it is a common and
expected case in the code paths.

Also removed some logging previously added for debugging this issue.
Merge pull request #3092 from davidegrohmann/2.2-avoid-unboud-wait

Add a timeout on the failedLatch which waits for the master to disappear
Merge pull request #3094 from thobe/2.2-counts-store

Number of relationships given node label.
created disk-backed recordkeeper/ verifier so that we can run experiments on large files
Merge pull request #3056 from davidegrohmann/2.1-cleanup-eidetic-req-monitor

[2.1] Cleanup EideticRequestMonitor
Merge branch '2.1-maint' into 2.2-merge-2.1

Conflicts:
	enterprise/ha/src/test/java/org/neo4j/ha/monitoring/EideticRequestMonitor.java
	enterprise/ha/src/test/java/org/neo4j/ha/monitoring/RemoteRequestMonitoringIT.java
added informative metadata to page cache stress testing
Merge pull request #3090 from martinfurmanski/fix-two-ha-com-issues

Fix an issue reading transaction logs over network.
Ignore a flaky test in an unused component, which is going to be removed.
making page cache stress test working directory be configurable so that we can run it on certain locations on the build
cleaned up references to enterprise-io
Merge pull request #3107 from lutovich/2.2-merge-2.1

2.2 <-[:merge]- 2.1