Extend symbolic language support

This MR reintroduces a number of missing features relating to the symbolic language to the new backend.

• AddressOf
• Logarithm, Hyperbolic and inverse trigonometric functions
• Multi-Argument and integer min/max
• Symbolic C-style integer remainder
• ConditionalFieldAccess

The documentation on the symbolic language is slightly extended, and a few bug fixes are included.

added feature label

requested review from @he66coqe

assigned to @da15siwa

changed the description

added 2 commits

• 6be4b5af - Fix multiarg min/max freeze, introduce test case, fix MathFunction equality
• 7f6bb130 - move c-intdiv implementations to pystencils.utils

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approved this merge request

mentioned in commit d6621ef9

merged

mentioned in task #87