Add EMPLACE_TYPE support for B+TREE, DICT, RB-TREE, BUFFER, CONCURRENT

[P-p-H-d]

Add basic & naive implementation of emplace* functions for:

• B+TREE (both set & map) [DONE]
• DICT [DONE]
• RB-TREE [DONE]
• BUFFER, [DONE]
• CONCURRENT [DONE]

[P-p-H-d]

Done for RB Tree

[P-p-H-d]

The main problem for the remaining emplace functions is to find how to name the emplace function:

• from the set of emplace functions of the key (empty, suffix1a, ...)
• from the set of emplace functions of the value (empty, suffix1b, ...) how to name the emplace function so that it is natural to read and without any ambiguity?

name_emplace_suffix1b_on_suffix1a(container, value, key) may be natural english but the order of the arguments are different than name_set_at(container, key, value) and C++ emplace

See also https://cplusplus.com/reference/vector/vector/emplace/

[P-p-H-d]

I'll probably go on with "name_key_emplace_suffix1a_val_suffix1b" with suffix1a being the key and suffix1b the value even if it is not perfect.