switch to sel={dim}={method}::{value} notation to specify selector method

[vincentsarago]

match earth-mover/xpublish-tiles#164 (🙏 @dcherian)

Before this PR we used sel-method=nearest parameter but this limited the possibility to use different method for different dimension.

With this PR we introduce a new string format for selectors: sel={dimension}=({method}::)?{value}

[dcherian]

Haha I love that we're stealing ideas from each other. Hurray for open source!

[vincentsarago]

I'm still a bit hesitant about the :: notation.

In other titiler dependencies we use pipe | to handle complexe query parameters (e.g asset_bidx={asset}|1,2,3) so maybe we should also use | here: sel={dimension}={value}(|{method})?

[abarciauskas-bgse]

Do we have a sense of pros and cons for each syntax option (i.e. |, ::, others?) for selector parameters?

[vincentsarago]

Do we have a sense of pros and cons for each syntax option (i.e. |, ::, others?) for selector parameters?

both are uncommon delimiters and would need to be URI encoded

[vincentsarago]

@dcherian can you share why you went with :: as separator?