Improvements for legends and time axes

[numeredev]

DESCRIPTION

What does your feature request improve on? Please describe.
Legends are sometimes covering important areas. Would be better to move them out of the plot boundaries. Time axes could accept a custom tick stepping to make hours, days, weeks more visible.

Describe the solution you'd like
Add two new options to the plot options:

• legendstyle should accept additional positions for the outside, e.g. legendstyle=outerright
• timeaxes should accept an optional stepping value, e.g. timeaxes=("x", "MM/YY", 7*3600*24) for a week tick stepping

Additional context
Add any other context or screenshots about the feature request here.

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DEVS' SECTION

ANALYSIS

(Describe, what's the issue and which changes have to be made)

IMPLEMENTATION STEPS

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DOCUMENTATION STEPS

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PULL REQUEST

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