Add some missing features

[easbar]

• negative numbers in operator expressions like max_speed * -0.2
• encoded value expressions like <ev>.ordinal() and edge.getDistance() (both numeric)
• some math functions like Math.abs/sqrt
• boolean encoded value-like expressions like edge.getName().contains("xyz")

See here what is allowed on the server side: https://github.com/graphhopper/graphhopper/blob/2140131ec079e21b7e7f05865a3b77913b0d9acc/core/src/main/java/com/graphhopper/routing/weighting/custom/ConditionalExpressionVisitor.java#L41-L42